Sample records for nambu-goldstone dark matter

We propose a scenario in which dark energy and darkmatter are described in a unified manner. The ultralight pseudo-Nambu-Goldstone (pNG) boson, A, naturally explains the observed magnitude of dark energy, while the bosonic supersymmetry partner of the pNG boson, B, can be a dominant component of darkmatter. The decay of B into a pair of electron and positron may explain the 511 keV γ ray from the Galactic Center

The presence of a hot darkmatter component has been hinted at 3σ by a combination of the results from different cosmological observations. We examine a possibility that pseudo Nambu- Goldstone bosons account for both hot and cold darkmatter components. We show that the QCD axions can do the job for the axion decay constant f a 10 ) GeV, if they are produced by the saxion decay and the domain wall annihilation. We also investigate the cases of thermal QCD axions, pseudo Nambu-Goldstone bosons coupled to the standard model sector through the Higgs portal, and axions produced by modulus decay.

We study natural composite cold darkmatter candidates which are pseudo Nambu-Goldstone bosons (pNGB) in models of dynamical electroweak symmetry breaking. Some of these can have a significant thermal relic abundance, while others must be mainly asymmetric darkmatter. By considering the thermal...... abundance alone we find a lower bound of MW on the pNGB mass when the (composite) Higgs is heavier than 115 GeV. Being pNGBs, the darkmatter candidates are in general light enough to be produced at the LHC....

The presence of a hot darkmatter component has been hinted at 3{sigma} by a combination of the results from different cosmological observations. We examine a possibility that pseudo Nambu- Goldstone bosons account for both hot and cold darkmatter components. We show that the QCD axions can do the job for the axion decay constant f{sub a}Nambu-Goldstone bosons coupled to the standard model sector through the Higgs portal, and axions produced by modulus decay.

The pseudo-Nambu-Goldstone Boson (PNGB) potential, defined through the amplitude M {sup 4} and width f of its characteristic potential V (φ) = M {sup 4}[1 + cos(φ/ f )], is one of the best-suited models for the study of thawing quintessence. We analyse its present observational constraints by direct numerical solution of the scalar field equation of motion. Observational bounds are obtained using Supernovae data, cosmic microwave background temperature, polarization and lensing data from Planck , direct Hubble constant constraints, and baryon acoustic oscillations data. We find the parameter ranges for which PNGB quintessence gives a viable theory for dark energy. This exact approach is contrasted with the use of an approximate equation-of-state parametrization for thawing theories. We also discuss other possible parameterization choices, as well as commenting on the accuracy of the constraints imposed by Planck alone. Overall our analysis highlights a significant prior dependence to the outcome coming from the choice of modelling methodology, which current data are not sufficient to override.

In the presence of approximate global symmetries that forbid relevant interactions, strongly coupled light DarkMatter (DM) can appear weakly coupled at small-energy and generate a sizable relic abundance. Fundamental principles like unitarity restrict these symmetries to a small class, where the leading interactions are captured by effective operators up to dimension-8. Chiral symmetry, spontaneously broken global symmetries and non-linearly realized supersymmetry are examples of this. Their DM candidates (composite fermions, pseudo-Nambu-Goldstone Bosons and Goldstini) are interesting targets for LHC missing-energy searches.

We show that a pseudo Nambu-Goldstone boson, with a potential of the form V(φ)=Λ 4 [1±cos(φ/f)], can naturally give rise to an epoch of inflation in the early Universe. Successful inflation can be achieved if f∼m Pl and Λ∼m GUT . Such mass scales arise in particle-physics models with a gauge group that becomes strongly interacting at a scale ∼Λ, e.g., as can happen in superstring theories. The density fluctuation spectrum is non-scale-invariant, with extra power on large length scales

We examine the impact of the expected reach of the LHC and the XENON1T experiments on the parameter space of the minimal classically scale invariant extension of the standard model (SM), where all the mass scales are induced dynamically by means of the Coleman-Weinberg mechanism. In this framework, the SM content is enlarged by the addition of one complex gauge-singlet scalar with a scale invariant and C P -symmetric potential. The massive pseudoscalar component, protected by the C P symmetry, forms a viable darkmatter candidate, and three flavors of the right-handed Majorana neutrinos are included to account for the nonzero masses of the SM neutrinos via the seesaw mechanism. The projected constraints on the parameter space arise by applying the ATLAS heavy Higgs discovery prospects, with an integrated luminosity of 300 and 3000 fb-1 at √{s }=14 TeV , to the pseudo-Nambu-Goldstone boson of the (approximate) scale symmetry, as well as by utilizing the expected reach of the XENON1T direct detection experiment for the discovery of the pseudoscalar darkmatter candidate. A null-signal discovery by these future experiments implies that vast regions of the model's parameter space can be thoroughly explored; the combined projections are expected to confine a mixing between the SM and the singlet sector to very small values while probing the viability of the TeV scale pseudoscalar's thermal relic abundance as the dominant darkmatter component in the Universe. Furthermore, the vacuum stability and triviality requirements of the framework up to the Planck scale are studied, and the viable region of the parameter space is identified. The results are summarized in extensive exclusion plots, incorporating additionally the prior theoretical and experimental bounds for comparison.

We introduce a lattice fermion model in one spatial dimension with supersymmetry (SUSY) but without particle number conservation. The Hamiltonian is defined as the anticommutator of two nilpotent supercharges Q and Q†. Each supercharge is built solely from spinless fermion operators and depends on a parameter g . The system is strongly interacting for small g , and in the extreme limit g =0 , the number of zero-energy ground states grows exponentially with the system size. By contrast, in the large-g limit, the system is noninteracting and SUSY is broken spontaneously. We study the model for modest values of g and show that under certain conditions spontaneous SUSY breaking occurs in both finite and infinite chains. We analyze the low-energy excitations both analytically and numerically. Our analysis suggests that the Nambu-Goldstone fermions accompanying the spontaneous SUSY breaking have cubic dispersion at low energies.

In this review we discuss how the models of neutrino masses can accommodate solutions to the problem of matter-antimatter asymmetry in the universe, dark energy or cosmological constant problem and darkmatter candidates. The matter-antimatter asymmetry is explained by leptogenesis, originating from the lepton number violation associated with the neutrino masses. The dark energy problem is correlated with a mass varying neutrinos, which could originate from a pseudo-Nambu-Goldstone boson. In some radiative models of neutrino masses, there exists a Higgs doublet that does not acquire any vacuum expectation value. This field could be inert and the lightest inert particle could then be a darkmatter candidate. We reviewed these scenarios in connection with models of neutrino masses with right-handed neutrinos and with triplet Higgs scalars

We study the darkmatter phenomenology of non-minimal composite Higgs models with SO(7) broken to the exceptional group G{sub 2}. In addition to the Higgs, three pseudo-Nambu-Goldstone bosons arise, one of which is electrically neutral. A parity symmetry is enough to ensure this resonance is stable. In fact, if the breaking of the Goldstone symmetry is driven by the fermion sector, this Z{sub 2} symmetry is automatically unbroken in the electroweak phase. In this case, the relic density, as well as the expected indirect, direct and collider signals are then uniquely determined by the value of the compositeness scale, f. Current experimental bounds allow one to account for a large fraction of the darkmatter of the Universe if the darkmatter particle is part of an electroweak triplet. The totality of the relic abundance can be accommodated if instead this particle is a composite singlet. In both cases, the scale f and the darkmatter mass are of the order of a few TeV. (orig.)

The MIT bag model for the pion is improved and extended in such a way that the pion does not have spurious center-of-mass motions; perturbative gluon contributions to the pion mass msub(π) and decay constant fsub(π) are both calculated to lowest order in αsub(s). The pion is a Nambu-Goldstone boson in the sense that the vacuum in the bag refers to massive constituent quarks, but not so massless current quarks. The transformation of Nambu and Jona-Lasinio between massive and massless quarks is utilized in the computation of fsub(π), the result of which strongly suggests that quarks in the pion are correlated, characterized by a correlation momentum which is proportional 300 MeV/c. The vacuum expectation value for the massless quark condensate is calculated to be proportional0.04 GeV 3 , corresponding to a current quark mass of proportional4 MeV. The requirement that msub(π) approaches zero in a manner consistent with PCAC constrains the bag energy to be msub(π)/4. (orig.)

We consider an extension of the Standard Model with the global symmetry-breaking pattern SO(5)/SO(4), where the Higgs boson arises as a pseudo-Nambu-Goldstone boson. The scalar content of the theory consists of a Standard-Model-like Higgs field and an extra real scalar field. The flavor sector...

The Peccei-Quinn (PQ) solution of the strong CP problem requires the existence of axions, which are viable candidates for darkmatter. If the Nambu-Goldstone potential of the PQ model is replaced by a potential V(|Phi|) admitting a tracker solution, the scalar field |Phi| can account for dark energy, while the phase of Phi yields axion darkmatter. If V is a supergravity (SUGRA) potential, the model essentially depends on a single parameter, the energy scale Lambda. Once we set Lambda approximately equal to 10(10) GeV at the quark-hadron transition, |Phi| naturally passes through values suitable to solve the strong CP problem, later growing to values providing fair amounts of darkmatter and dark energy.

In the light of recent possible tensions in the Hubble constant H0 and the structure growth rate σ8 between the Planck and other measurements, we investigate a hidden-charged darkmatter (DM) model where DM interacts with hidden chiral fermions, which are charged under the hidden SU(N) and U(1) gauge interactions. The symmetries in this model assure these fermions to be massless. The DM in this model, which is a Dirac fermion and singlet under the hidden SU(N), is also assumed to be charged under the U(1) gauge symmetry, through which it can interact with the chiral fermions. Below the confinement scale of SU(N), the hidden quark condensate spontaneously breaks the U(1) gauge symmetry such that there remains a discrete symmetry, which accounts for the stability of DM. This condensate also breaks a flavor symmetry in this model and Nambu-Goldstone bosons associated with this flavor symmetry appear below the confinement scale. The hidden U(1) gauge boson and hidden quarks/Nambu-Goldstone bosons are components of dark radiation (DR) above/below the confinement scale. These light fields increase the effective number of neutrinos by δNeff ≃ 0.59 above the confinement scale for N = 2, resolving the tension in the measurements of the Hubble constant by Planck and Hubble Space Telescope if the confinement scale is ≲1 eV. DM and DR continuously scatter with each other via the hidden U(1) gauge interaction, which suppresses the matter power spectrum and results in a smaller structure growth rate. The DM sector couples to the Standard Model sector through the exchange of a real singlet scalar mixing with the Higgs boson, which makes it possible to probe our model in DM direct detection experiments. Variants of this model are also discussed, which may offer alternative ways to investigate this scenario.

We consider an extended Nambu--Jona-Lasinio model including both (q \\bar q)- and (qq)-interactions with two light-quark flavors in the presence of a single (quark density) chemical potential. In the color superconducting phase of the quark matter the color SU(3) symmetry is spontaneously broken down to SU(2). If the usual counting of Goldstone bosons would apply, five Nambu-Goldstone (NG) bosons corresponding to the five broken color generators should appear in the mass spectrum. Unlike that ...

In the spirit of the top-quark condensation, we propose a model which has a naturally light composite Higgs boson, "tHiggs" (ht0), to be identified with the 126 GeV Higgs discovered at the LHC. The tHiggs, a bound state of the top quark and its flavor (vectorlike) partner, emerges as a pseudo-Nambu-Goldstone boson (NGB), "top-mode pseudo-Nambu-Goldstone boson," together with the exact NGBs to be absorbed into the W and Z bosons as well as another (heavier) top-mode pseudo-Nambu-Goldstone bosons (CP-odd composite scalar, At0). Those five composite (exact/pseudo-) NGBs are dynamically produced simultaneously by a single supercritical four-fermion interaction having U(3)×U(1) symmetry which includes the electroweak symmetry, where the vacuum is aligned by a small explicit breaking term so as to break the symmetry down to a subgroup, U(2)×U(1)', in a way not to retain the electroweak symmetry, in sharp contrast to the little Higgs models. The explicit breaking term for the vacuum alignment gives rise to a mass of the tHiggs, which is protected by the symmetry and hence naturally controlled against radiative corrections. Realistic top-quark mass is easily realized similarly to the top-seesaw mechanism by introducing an extra (subcritical) four-fermion coupling which explicitly breaks the residual U(2)'×U(1)' symmetry with U(2)' being an extra symmetry besides the above U(3)L×U(1). We present a phenomenological Lagrangian of the top-mode pseudo-Nambu-Goldstone bosons along with the Standard Model particles, which will be useful for the study of the collider phenomenology. The coupling property of the tHiggs is shown to be consistent with the currently available data reported from the LHC. Several phenomenological consequences and constraints from experiments are also addressed.

The two approaches of consistent quantum field theory for systems of the trapped Bose-Einstein condensates are known, one is the Bogoliubov-de Gennes approach and the other is the generalized Bogoliubov approach. In this paper, we investigate the relation between the two approaches and show that they are formally equivalent to each other. To do this one must carefully treat the Nambu-Goldstone mode which plays a crucial role in the condensation. It is emphasized that the choice of vacuum is physically relevant

We consider a composite model where both the Higgs and a complex scalar χ, which is the darkmatter (DM) candidate, arise as light pseudo Nambu-Goldstone bosons (pNGBs) from a strongly coupled sector with TeV scale confinement. The global symmetry structure is SO(7)/SO(6), and the DM is charged under an exact U(1)DM ⊂ SO(6) that ensures its stability. Depending on whether the χ shift symmetry is respected or broken by the coupling of the top quark to the strong sector, the DM can be much lighter than the Higgs or have a weak-scale mass. Here we focus primarily on the latter possibility. We introduce the lowest-lying composite resonances and impose calculability of the scalar potential via generalized Weinberg sum rules. Compared to previous analyses of pNGB DM, the computation of the relic density is improved by fully accounting for the effects of the fermionic top partners. This plays a crucial role in relaxing the tension with the current DM direct detection constraints. The spectrum of resonances contains exotic top partners charged under the U(1)DM, whose LHC phenomenology is analyzed. We identify a region of parameters with f = 1.4 TeV and 200 GeV ≲ m χ ≲ 400 GeV that satisfies all existing bounds. This DM candidate will be tested by XENON1T in the near future.

It was suggested that supersymmetry (SUSY) is broken at finite temperature, and as a result of the symmetry breaking, a Nambu-Goldstone fermion (goldstino) related to SUSY breaking appears. Since dispersion relations of quarks and gluons are almost degenerate at extremely high temperature, quasi-zero energy quark excitation was suggested to exist in quark-gluon plasma (QGP), though QCD does not have exact SUSY. On the other hand, in condensed matter system, a setup of cold atom system in which the Hamiltonian has SUSY was proposed, the goldstino was suggested to exist, and the dispersion relation of that mode at zero temperature was obtained recently. In this presentation, we obtain the expressions for the dispersion relation of the goldstino in cold atom system at finite temperature, and compare it with the dispersion of the quasi zero-mode in QGP. Furthermore, we show that the form of the dispersion relation of the goldstino can be understood by using an analogy with a magnon in ferromagnet. We also discuss on how the dispersion relation of the goldstino is reflected in observable quantities in experiment. (author)

In a one-generation fermion condensate scheme of electroweak symmetry breaking, it is proven that at finite temperature T below the symmetry restoration temperature T c , a massive Higgs boson and three massless Nambu-Goldstone bosons could emerge from the spontaneous breaking of electroweak group SU L (2)xU Y (1)→U Q (1) if the two fermion flavors in the one generation are mass-degenerate, thus the Goldstone Theorem is rigorously valid in this case. However, if the two fermion flavors have unequal masses, owing to 'thermal fluctuation', the Goldstone Theorem will be true only approximately for a very large momentum cut-off Λ in zero temperature fermion loop or for low energy scales. All possible pinch singularities are proven to cancel each other, as is expected in a real-time thermal field theory. (author)

Scenarios where gravitinos with GeV masses make up darkmatter are known to be in tension with high reheating temperatures, as required by e.g. thermal leptogenesis. This tension comes from the longevity of the NLSPs, which can destroy the successful predictions of the standard primordial nucleosynthesis. However, a small violation of matter parity can open new decay channels for the NLSP, avoiding the BBN problems, while being compatible with experimental cosmic-ray constraints. In this paper, we propose a model where matter parity, which we assume to be embedded in the U(1) B-L gauge symmetry, is broken dynamically in a hidden sector at low scales. This can naturally explain the smallness of the matter parity breaking in the visible sector. We discuss the dynamics of the corresponding pseudo Nambu-Goldstone modes of B-L breaking in the hidden sector, and we comment on typical cosmic-ray and collider signatures in our model. (orig.)

Scenarios where gravitinos with GeV masses make up darkmatter are known to be in tension with high reheating temperatures, as required by e.g. thermal leptogenesis. This tension comes from the longevity of the NLSPs, which can destroy the successful predictions of the standard primordial nucleosynthesis. However, a small violation of matter parity can open new decay channels for the NLSP, avoiding the BBN problems, while being compatible with experimental cosmic-ray constraints. In this paper, we propose a model where matter parity, which we assume to be embedded in the U(1){sub B-L} gauge symmetry, is broken dynamically in a hidden sector at low scales. This can naturally explain the smallness of the matter parity breaking in the visible sector. We discuss the dynamics of the corresponding pseudo Nambu-Goldstone modes of B-L breaking in the hidden sector, and we comment on typical cosmic-ray and collider signatures in our model. (orig.)

Motivated by the Nambu--Jona-Lasinio model of light mesons, we introduce a covariant separable interaction to model the structure of relativistic quark-antiquark systems. The Schwinger-Dyson equation for the quark self-energy is solved analytically, generating a dynamical quark mass through spontaneous breaking of chiral symmetry, and yielding a pion which has zero mass in the chiral limit. The Bethe-Salpeter vertex function for this q bar q pion, which has a momentum distribution and composite structure associated with the interaction, is obtained analytically. Using this vertex function, and a similar one for the ρ meson, we calculate the electromagnetic observables of this composite Nambu-Goldstone boson, including effects from ρ-meson dominance processes. Our calculation takes the composite structure of the mesons into account. The ρ-meson effects are found to be very small in the pion charge form factor, but substantial in the charge radius. Using the model, predictions are made for γ * π 0 →γ and ρπγ transition form factors

The calculation of finite temperature contributions to the scalar potential in a quantum field theory is similar to the calculation of loop corrections at zero temperature. In natural extensions of the Standard Model where loop corrections to the Higgs potential cancel between Standard Model degrees of freedom and their symmetry partners, it is interesting to contemplate whether finite temperature corrections also cancel, raising the question of whether a broken phase of electroweak symmetry may persist at high temperature. It is well known that this does not happen in supersymmetric theories because the thermal contributions of bosons and fermions do not cancel each other. However, for theories with same spin partners, the answer is less obvious. Using the Twin Higgs model as a benchmark, we show that although thermal corrections do cancel at the level of quadratic divergences, subleading corrections still drive the system to a restored phase. We further argue that our conclusions generalize to other well-known extensions of the Standard Model where the Higgs is rendered natural by being the pseudo-Nambu-Goldstone mode of an approximate global symmetry.

The construction of effective actions for Nambu-Goldstone bosons, and the nonlinear sigma model, usually requires a target coset space $G/H$. Recent progresses uncovered a new formulation using only IR data, without reference to $G/H$, by imposing the Adler's zero condition, which can be seen to originate from the superselection rule in the space of degenerate vacua. The IR construction imposes a nonlinear shift symmetry on the Lagrangian to enforce the correct single soft limit amid constraints of the unbroken group $H$. We present a systematic study on the consequence of the Adler's zero condition in correlators of nonlinear sigma model, by deriving the conserved current and the Ward identity associated with the nonlinear shift symmetry, and demonstrate how the old-fashioned current algebra emerges. The Ward identity leads to a new representation of on-shell amplitudes, which amounts to bootstrapping the higher point amplitudes from lower point amplitudes and adding new vertices to satisfy the Adler's condi...

We explore a model based on the classically scale-invariant standard model (SM) with a strongly coupled vectorlike dynamics, which is called hypercolor (HC). The scale symmetry is dynamically broken by the vectorlike condensation at the TeV scale, so that the SM Higgs acquires the negative mass squared by the bosonic seesaw mechanism to realize the electroweak symmetry breaking. An elementary pseudoscalar S is introduced to give masses for the composite Nambu-Goldstone bosons (HC pions): The HC pion can be a good target to explore through a diphoton channel at the LHC. As a consequence of the bosonic seesaw, the fluctuating mode of S , which we call s , develops tiny couplings to the SM particles and is predicted to be very light. The s predominantly decays to a diphoton and can behave as invisible axionlike darkmatter. The mass of the s darkmatter is constrained by currently available cosmological and astrophysical limits to be 10-4 eV ≲ms≲1 eV . We find that a sufficient amount of relic abundance for the s darkmatter can be accumulated via the coherent oscillation. The detection potential in microwave cavity experiments is also addressed.

We consider an extended Nambu-Jona-Lasinio model including both (qq-bar) and (qq) interactions with two light-quark flavors in the presence of a single (quark density) chemical potential. In the color superconducting phase of the quark matter the color SU c (3) symmetry is spontaneously broken down to SU c (2). If the usual counting of Goldstone bosons would apply, five Nambu-Goldstone (NG) bosons corresponding to the five broken color generators should appear in the mass spectrum. Unlike that expectation, we find only three gapless diquark excitations of quark matter. One of them is an SU c (2) singlet; the remaining two form an SU c (2) (anti)doublet and have a quadratic dispersion law in the small momentum limit. These results are in agreement with the Nielsen-Chadha theorem, according to which NG bosons in Lorentz-noninvariant systems, having a quadratic dispersion law, must be counted differently. The origin of the abnormal number of NG bosons is shown to be related to a nonvanishing expectation value of the color charge operator Q 8 reflecting the lack of color neutrality of the ground state. Finally, by requiring color neutrality, two massive diquarks are argued to become massless, resulting in a normal number of five NG bosons with the usual linear dispersion laws

Full Text Available I give a review of the development of the concept of darkmatter. The darkmatter story passed through several stages from a minor observational puzzle to a major challenge for theory of elementary particles. Modern data suggest that darkmatter is the dominant matter component in the Universe, and that it consists of some unknown non-baryonic particles. Darkmatter is the dominant matter component in the Universe, thus properties of darkmatter particles determine the structure of the cosmic web.

Darkmatter, baryonic matter, and dark energy have different properties but contribute comparable energy density to the present Universe. We point out that they may have a common origin. As the dark energy has a scale far lower than all known scales in particle physics but very close to neutrino masses, while the excess matter over antimatter in the baryonic sector is probably related to the neutrino-mass generation, we unify the origin of the dark and visible universe in a variant of the seesaw model. In our model (i) the darkmatter relic density is a darkmatter asymmetry emerged simultaneously with the baryon asymmetry from leptogenesis; (ii) the dark energy is due to a pseudo-Nambu-Goldstone-Boson associated with the neutrino-mass generation.

One of the greatest mysteries in the cosmos is that it is mostly dark. That is, not only is the night sky dark, but also most of the matter and the energy in the universe is dark. For every atom visible in planets, stars and galaxies today there exists at least five or six times as much 'DarkMatter' in the universe. Astronomers and particle physicists today are seeking to unravel the nature of this mysterious but pervasive darkmatter, which has profoundly influenced the formation of structure in the universe. Dark energy remains even more elusive, as we lack candidate fields that emerge from well established physics. I will describe various attempts to measure darkmatter by direct and indirect means, and discuss the prospects for progress in unravelling dark energy.

What You See Ain't What. You Got, Resonance, Vol.4,. No.9,1999. DarkMatter. 2. DarkMatter in the Universe. Bikram Phookun and Biman Nath. In Part 11 of this article we learnt that there are compelling evidences from dynamics of spiral galaxies, like our own, that there must be non-luminous matter in them. In this.

These proceedings represent papers presented at the Astrophysics conference in Maryland, organized by NASA Goddard Space Flight Center and the University of Maryland. The topics covered included low mass stars as darkmatter, darkmatter in galaxies and clusters, cosmic microwave background anisotropy, cold and hot darkmatter, and the large scale distribution and motions of galaxies. There were eighty five papers presented. Out of these, 10 have been abstracted for the Energy Science and Technology database

One of the biggest scientific mysteries of our time resides in the identification of the particles that constitute a large fraction of the mass of our Universe, generically known as darkmatter. We review the observations and the experimental data that imply the existence of darkmatter. We briefly discuss the properties of the two best dark-matter candidate particles and the experimental techniques presently used to try to discover them. Finally, we mention a proposed project that has recently emerged within the Mexican community to look for darkmatter

As if this was not enough, it turns out that if our knowledge of ... are thought to contain darkmatter, although the evidences from them are the .... protons, electrons, neutrons ... ratio of protons to neutrons was close to unity then as they were in ...

The study of gas clouds orbiting in the outer regions of spiral galaxies has revealed that their gravitational at- traction is much larger than the stars alone can provide. Over the last twenty years, astronomers have been forced to postulate the presence of large quantities of 'darkmatter' to explain their observations. They are ...

The book begins with the papers devoted to the experimental search of signatures of the darkmatter which governs the evolution of the Universe as a whole. A series of contributions describe the presently considered experimental techniques (cryogenic detectors, supraconducting detectors...). A real dialogue concerning these techniques has been instaured between particle physicists and astrophysicists. After the progress report of the particle physicists, the book provides the reader with an updated situation concerning the research in cosmology. The second part of the book is devoted to the analysis of the backgrounds at different energies such as the possible role of the cooling flows in the constitution of massive galactic halos. Any search of darkmatter implies necessarily the analysis of the spatial distributions of the large scale structures of the Universe. This report is followed by a series of statistical analyses of these distributions. These analyses concern mainly universes filled up with cold darkmatter. The last paper of this third part concerns the search of clustering in the spatial distribution of QSOs. The presence of darkmatter should affect the solar neighborhood and related to the existence of galactic haloes. The contributions are devoted to the search of such local darkmatter. Primordial nucleosynthesis provides a very powerful tool to set up quite constraining limitations on the overall baryonic density. Even if on takes into account the inhomogeneities in density possibly induced by the Quark-Hadron transition, this baryonic density should be much lower than the overall density deduced from the dynamical models of Universe or the inflationary theories

It is a puzzle why the densities of darkmatter and dark energy are nearly equal today when they scale so differently during the expansion of the universe. This conundrum may be solved if there is a coupling between the two dark sectors. In this Letter we assume that darkmatter is made of cold relics with masses depending exponentially on the scalar field associated to dark energy. Since the dynamics of the system is dominated by an attractor solution, the darkmatter particle mass is forced to change with time as to ensure that the ratio between the energy densities of darkmatter and dark energy become a constant at late times and one readily realizes that the present-day darkmatter abundance is not very sensitive to its value when darkmatter particles decouple from the thermal bath. We show that the dependence of the present abundance of cold darkmatter on the parameters of the model differs drastically from the familiar results where no connection between dark energy and darkmatter is present. In particular, we analyze the case in which the cold darkmatter particle is the lightest supersymmetric particle

We study the possibility that a dark group, a gauge group with particles interacting with the standard model particles only via gravity, is responsible for containing the dark energy and darkmatter required by present day observations. We show that it is indeed possible and we determine the constrains for the dark group. The non-perturbative effects generated by a strong gauge coupling constant can de determined and a inverse power law scalar potential IPL for the dark meson fields is generated parameterizing the dark energy. On the other hand it is the massive particles, e.g., dark baryons, of the dark gauge group that give the corresponding darkmatter. The mass of the dark particles is of the order of the condensation scale Λ c and the temperature is smaller then the photon's temperature. The darkmatter is of the warm matter type. The only parameters of the model are the number of particles of the dark group. The allowed values of the different parameters are severely restricted. The dark group energy density at Λ c must be Ω DGc ≤0.17 and the evolution and acceptable values of darkmatter and dark energy leads to a constrain of Λ c and the IPL parameter n giving Λ c =O(1-10 3 ) eV and 0.28≤n≤1.04

It's a dark, dark universe out there, and I don't mean because the night sky is black. After all, once you leave the shadow of the Earth and get out into space, you're surrounded by countless lights glittering everywhere you look. But for all of Sagan's billions and billions of stars and galaxies, it's a jaw-dropping fact that the ordinary kind of…

We explore the feasibility and astrophysical consequences of a new long-range U(1) gauge field ('dark electromagnetism') that couples only to darkmatter, not to the standard model. The darkmatter consists of an equal number of positive and negative charges under the new force, but annihilations are suppressed if the dark-matter mass is sufficiently high and the dark fine-structure constant α-circumflex is sufficiently small. The correct relic abundance can be obtained if the darkmatter also couples to the conventional weak interactions, and we verify that this is consistent with particle-physics constraints. The primary limit on α-circumflex comes from the demand that the darkmatter be effectively collisionless in galactic dynamics, which implies α-circumflex -3 for TeV-scale darkmatter. These values are easily compatible with constraints from structure formation and primordial nucleosynthesis. We raise the prospect of interesting new plasma effects in dark-matter dynamics, which remain to be explored.

We study a mechanism where the darkmatter number density today arises from asymmetries generated in the dark sector in the early Universe, even though the total darkmatter number remains zero throughout the history of the Universe. The darkmatter population today can be completely symmetric, with annihilation rates above those expected from thermal weakly interacting massive particles. We give a simple example of this mechanism using a benchmark model of flavored darkmatter. We discuss the experimental signatures of this setup, which arise mainly from the sector that annihilates the symmetric component of darkmatter.

In the first two of these lectures, I present the evidence for baryonic darkmatter and describe possible forms that it may take. The final lecture discusses formation of baryonic darkmatter, and sets the cosmological context.

A fundamental question of astrophysics and cosmology is the nature of darkmatter. Astrophysical observations show clearly the existence of some kind of darkmatter, though they cannot yet reveal its nature. Darkmatter can consist of baryonic particles, or of other (known or unknown) elementary particles. Baryonic darkmatter probably exists in the form of dust, gas, or small stars. Other elementary particles constituting the darkmatter can possibly be measured in terrestrial experiments. Possibilities for darkmatter particles are neutrinos, axions and weakly interacting massive particles (WIMPs). While a direct detection of relic neutrinos seems at the moment impossible, there are experiments looking for baryonic darkmatter in the form of Massive Compact Halo Objects, and for particle darkmatter in the form of axions and WIMPS. (orig.)

This thesis discusses models for darkmatter (DM) and their behavior in the early universe. An important question is how phenomenological probes can directly search for signals of DM today. Another topic of investigation is how the DM and other processes in the early universe must evolve. Then, astrophysical bounds on early universe dynamics can constrain DM. We will consider these questions in the context of three classes of DM models--weakly interacting massive particles (WIMPs), axions, and primordial black holes (PBHs). Starting with WIMPs, we consider models where the DM is charged under the electroweak gauge group of the Standard Model. Such WIMPs, if generated by a thermal cosmological history, are constrained by direct detection experiments. To avoid present or near-future bounds, the WIMP model or cosmological history must be altered in some way. This may be accomplished by the inclusion of new states that coannihilate with the WIMP or a period of non-thermal evolution in the early universe. Future experiments are likely to probe some of these altered scenarios, and a non-observation would require a high degree of tuning in some of the model parameters in these scenarios. Next, axions, as light pseudo-Nambu-Goldstone bosons, are susceptible to quantum fluctuations in the early universe that lead to isocurvature perturbations, which are constrained by observations of the cosmic microwave background (CMB). We ask what it would take to allow axion models in the face of these strong CMB bounds. We revisit models where inflationary dynamics modify the axion potential and discuss how isocurvature bounds can be relaxed, elucidating the difficulties in these constructions. Avoiding disruption of inflationary dynamics provides important limits on the parameter space. Finally, PBHs have received interest in part due to observations by LIGO of merging black hole binaries. We ask how these PBHs could arise through inflationary models and investigate the opportunity

The present status of alternative forms of darkmatter, both baryonic and nonbaryonic, is reviewed. Alternative arguments are presented for the predominance of either cold darkmatter (CDM) or of baryonic darkmatter (BDM). Strategies are described for darkmatter detection, both for darkmatter that consists of weakly interacting relic particles and for darkmatter that consists of dark stellar remnants

We organize the effective (self)interaction terms for complex scalar darkmatter candidates which are either an isosinglet, isodoublet or an isotriplet with respect to the weak interactions. The classification has been performed ordering the operators in inverse powers of the darkmatter cutoff...... scale. We assume Lorentz invariance, color and charge neutrality. We also introduce potentially interesting darkmatter induced flavor-changing operators. Our general framework allows for model independent investigations of darkmatter properties....

We consider darkmatter models in which the mass splitting between the darkmatter particles and their annihilation products is tiny. Compared to the previously proposed Forbidden DarkMatter scenario, the mass splittings we consider are much smaller, and are allowed to be either positive or negative. To emphasize this modification, we dub our scenario “Impeded Dark Matter”. We demonstrate that Impeded DarkMatter can be easily realized without requiring tuning of model parameters. For negative mass splitting, we demonstrate that the annihilation cross-section for Impeded DarkMatter depends linearly on the darkmatter velocity or may even be kinematically forbidden, making this scenario almost insensitive to constraints from the cosmic microwave background and from observations of dwarf galaxies. Accordingly, it may be possible for Impeded DarkMatter to yield observable signals in clusters or the Galactic center, with no corresponding signal in dwarfs. For positive mass splitting, we show that the annihilation cross-section is suppressed by the small mass splitting, which helps light darkmatter to survive increasingly stringent constraints from indirect searches. As specific realizations for Impeded DarkMatter, we introduce a model of vector darkmatter from a hidden SU(2) sector, and a composite darkmatter scenario based on a QCD-like dark sector.

We consider darkmatter models in which the mass splitting between the darkmatter particles and their annihilation products is tiny. Compared to the previously proposed Forbidden DarkMatter scenario, the mass splittings we consider are much smaller, and are allowed to be either positive or negative. To emphasize this modification, we dub our scenario “Impeded Dark Matter”. We demonstrate that Impeded DarkMatter can be easily realized without requiring tuning of model parameters. For negative mass splitting, we demonstrate that the annihilation cross-section for Impeded DarkMatter depends linearly on the darkmatter velocity or may even be kinematically forbidden, making this scenario almost insensitive to constraints from the cosmic microwave background and from observations of dwarf galaxies. Accordingly, it may be possible for Impeded DarkMatter to yield observable signals in clusters or the Galactic center, with no corresponding signal in dwarfs. For positive mass splitting, we show that the annihilation cross-section is suppressed by the small mass splitting, which helps light darkmatter to survive increasingly stringent constraints from indirect searches. As specific realizations for Impeded DarkMatter, we introduce a model of vector darkmatter from a hidden SU(2) sector, and a composite darkmatter scenario based on a QCD-like dark sector.

We discuss several cosmological production mechanisms for nonthermal supermassive darkmatter and argue that darkmatter may he elementary particles of mass much greater than the weak scale. Searches for darkmatter should ma be limited to weakly interacting particles with mass of the order of the weak scale, but should extend into the supermassive range as well.

We discuss several cosmological production mechanisms for nonthermal supermassive darkmatter and argue that darkmatter may be elementary particles of mass much greater than the weak scale. Searches for darkmatter should not be limited to weakly interacting particles with mass of the order of the weak scale, but should extend into the supermassive range as well. copyright 1998 The American Physical Society

We discuss several cosmological production mechanisms for nonthermal supermassive darkmatter and argue that darkmatter may be elementary particles of mass much greater than the weak scale. Searches for darkmatter should not be limited to weakly interacting particles with mass of the order of the weak scale, but should extend into the supermassive range as well.

The distributions of darkmatter and baryons in the Universe are known to be very different: The darkmatter resides in extended halos, while a significant fraction of the baryons have radiated away much of their initial energy and fallen deep into the potential wells. This difference in morphology leads to the widely held conclusion that darkmatter cannot cool and collapse on any scale. We revisit this assumption and show that a simple model where darkmatter is charged under a "dark electromagnetism" can allow darkmatter to form gravitationally collapsed objects with characteristic mass scales much smaller than that of a Milky-Way-type galaxy. Though the majority of the darkmatter in spiral galaxies would remain in the halo, such a model opens the possibility that galaxies and their associated darkmatter play host to a significant number of collapsed substructures. The observational signatures of such structures are not well explored but potentially interesting.

The distributions of darkmatter and baryons in the Universe are known to be very different: The darkmatter resides in extended halos, while a significant fraction of the baryons have radiated away much of their initial energy and fallen deep into the potential wells. This difference in morphology leads to the widely held conclusion that darkmatter cannot cool and collapse on any scale. We revisit this assumption and show that a simple model where darkmatter is charged under a "dark electromagnetism" can allow darkmatter to form gravitationally collapsed objects with characteristic mass scales much smaller than that of a Milky-Way-type galaxy. Though the majority of the darkmatter in spiral galaxies would remain in the halo, such a model opens the possibility that galaxies and their associated darkmatter play host to a significant number of collapsed substructures. The observational signatures of such structures are not well explored but potentially interesting.

The continuous infall of darkmatter with low velocity dispersion in galactic halos leads to the formation of high density structures called caustics. Darkmatter caustics are of two kinds : outer and inner. Outer caustics are thin spherical shells surrounding galaxies while inner caustics have a more complicated structure that depends on the darkmatter angular momentum distribution. The presence of a darkmatter caustic in the plane of the galaxy modifies the gas density in its neighborhood which may lead to observable effects. Caustics are also relevant to direct and indirect darkmatter searches.

Recent cosmological as well as historical observations of rotational curves of galaxies strongly suggest the existence of darkmatter. It is also widely believed that darkmatter consists of unknown elementary particles. However, astrophysical observations based on gravitational effects alone do not provide sufficient information on the properties of darkmatter. In this study, the status of darkmatter searches is investigated by observing high-energy neutrinos from the sun and the earth and by observing nuclear recoils in laboratory targets. The successful detection of darkmatter by these methods facilitates systematic studies of its properties. Finally, the XMASS experiment, which is due to start at the Kamioka Observatory, is introduced

We propose a new mechanism for thermal darkmatter freeze-out, called codecaying darkmatter. Multicomponent dark sectors with degenerate particles and out-of-equilibrium decays can codecay to obtain the observed relic density. The darkmatter density is exponentially depleted through the decay of nearly degenerate particles rather than from Boltzmann suppression. The relic abundance is set by the darkmatter annihilation cross section, which is predicted to be boosted, and the decay rate of the dark sector particles. The mechanism is viable in a broad range of darkmatter parameter space, with a robust prediction of an enhanced indirect detection signal. Finally, we present a simple model that realizes codecaying darkmatter.

We introduce a new paradigm in Composite Dark Sectors, where the full Standard Model (including the Higgs boson) is extended with a strongly-interacting composite sector with global symmetry group G spontaneously broken to H is contained in G. We show that, under well-motivated conditions, the lightest neutral pseudo Nambu-Goldstone bosons are natural darkmatter candidates for they are protected by a parity symmetry not even broken in the electroweak phase. These models are characterized by only two free parameters, namely the typical coupling g D and the scale f D of the composite sector, and are therefore very predictive. We consider in detail two minimal scenarios, SU(3)/[SU(2) x U(1)] and [SU(2) 2 x U(1)]/[SU(2) x U(1)], which provide a dynamical realization of the Inert Doublet and Triplet models, respectively. We show that the radiatively-induced potential can be computed in a five-dimensional description with modified boundary conditions with respect to Composite Higgs models. Finally, the darkmatter candidates are shown to be compatible, in a large region of the parameter space, with current bounds from darkmatter searches as well as electroweak and collider constraints on new resonances.

Bose-Einstein condensates (BECs) confined in a two-dimensional (2D) harmonic trap are known to possess a hidden 2D Schrödinger symmetry, that is, the Schrödinger symmetry modified by a trapping potential. Spontaneous breaking of this symmetry gives rise to a breathing motion of the BEC, whose oscillation frequency is robustly determined by the strength of the harmonic trap. In this paper, we demonstrate that the concept of the 2D Schrödinger symmetry can be applied to predict the nature of three-dimensional (3D) collective modes propagating along a condensate confined in an elongated trap. We find three kinds of collective modes whose existence is robustly ensured by the Schrödinger symmetry, which are physically interpreted as one breather mode and two Kelvin-ripple complex modes, i.e., composite modes in which the vortex core and the condensate surface oscillate interactively. We provide analytical expressions for the dispersion relations (energy-momentum relation) of these modes using the Bogoliubov theory [D. A. Takahashi and M. Nitta, Ann. Phys. 354, 101 (2015), 10.1016/j.aop.2014.12.009]. Furthermore, we point out that these modes can be interpreted as "quasi-massive-Nambu-Goldstone (NG) modes", that is, they have the properties of both quasi-NG and massive NG modes: quasi-NG modes appear when a symmetry of a part of a Lagrangian, which is not a symmetry of a full Lagrangian, is spontaneously broken, while massive NG modes appear when a modified symmetry is spontaneously broken.

Can darkmatter be stabilized by charge conservation, just as the electron is in the standard model? We examine the possibility that darkmatter is hidden, that is, neutral under all standard model gauge interactions, but charged under an exact (\\rm U)(1) gauge symmetry of the hidden sector. Such candidates are predicted in WIMPless models, supersymmetric models in which hidden darkmatter has the desired thermal relic density for a wide range of masses. Hidden charged darkmatter has many novel properties not shared by neutral darkmatter: (1) bound state formation and Sommerfeld-enhanced annihilation after chemical freeze out may reduce its relic density, (2) similar effects greatly enhance darkmatter annihilation in protohalos at redshifts of z ∼ 30, (3) Compton scattering off hidden photons delays kinetic decoupling, suppressing small scale structure, and (4) Rutherford scattering makes such darkmatter self-interacting and collisional, potentially impacting properties of the Bullet Cluster and the observed morphology of galactic halos. We analyze all of these effects in a WIMPless model in which the hidden sector is a simplified version of the minimal supersymmetric standard model and the darkmatter is a hidden sector stau. We find that charged hidden darkmatter is viable and consistent with the correct relic density for reasonable model parameters and darkmatter masses in the range 1 GeV ∼ X ∼< 10 TeV. At the same time, in the preferred range of parameters, this model predicts cores in the darkmatter halos of small galaxies and other halo properties that may be within the reach of future observations. These models therefore provide a viable and well-motivated framework for collisional darkmatter with Sommerfeld enhancement, with novel implications for astrophysics and darkmatter searches

Darkmatter is one of the most pressing problems in modern cosmology and particle physic research. This talk will motivate the existence of darkmatter by reviewing the main experimental evidence for its existence, the rotation curves of galaxies and the motions of galaxies about one another. It will then go on to review the corroborating theoretical motivations before combining all the supporting evidence to explore some of the possibilities for darkmatter along with its expected properties. This will lay the ground work for darkmatter detection. A number of differing techniques are being developed and used to detect darkmatter. These will be briefly discussed before the focus turns to cryogenic detection techniques. Finally, some preliminary results and expectations will be given for the Cryogenic DarkMatter Search (CDMS) experiment

A study is conducted of cold darkmatter (CDM) models in which clumpiness will inhere, using cosmic strings and textures suited to galaxy formation. CDM clumps of 10 million solar mass/cu pc density are generated at about z(eq) redshift, with a sizable fraction surviving. Observable implications encompass darkmatter cores in globular clusters and in galactic nuclei. Results from terrestrial darkmatter detection experiments may be affected by clumpiness in the Galactic halo.

This book is a new look at one of the hottest topics in contemporary science, DarkMatter. It is the pioneering text dedicated to sterile neutrinos as candidate particles for DarkMatter, challenging some of the standard assumptions which may be true for some DarkMatter candidates but not for all. So, this can be seen either as an introduction to a specialized topic or an out-of-the-box introduction to the field of DarkMatter in general. No matter if you are a theoretical particle physicist, an observational astronomer, or a ground based experimentalist, no matter if you are a grad student or an active researcher, you can benefit from this text, for a simple reason: a non-standard candidate for DarkMatter can teach you a lot about what we truly know about our standard picture of how the Universe works.

Darkmatter can be produced in the early universe via the freeze-in or freeze-out mechanisms. Both scenarios were investigated in references, but the production of darkmatters via the combination of these two mechanisms are not addressed. In this paper we propose a hybrid darkmatter model where darkmatters have two components with one component produced thermally and the other one produced non-thermally. We present for the first time the analytical calculation for the relic abundance of th...

Three teams of astronomers believe they have independently found evidence for darkmatter in our galaxy. A brief history of the search for darkmatter is presented. The use of microlensing-event observation for spotting darkmatter is described. The equipment required to observe microlensing events and three groups working on darkmatter detection are discussed. The three groups are the Massive Compact Halo Objects (MACHO) Project team, the Experience de Recherche d'Objets Sombres (EROS) team, and the Optical Gravitational Lensing Experiment (OGLE) team. The first apparent detections of microlensing events by the three teams are briefly reported.

The cosmological darkmatter problem is reviewed. The Big Bang Nucleosynthesis constraints on the baryon density are compared with the densities implied by visible matter, dark halos, dynamics of clusters, gravitational lenses, large-scale velocity flows, and the {Omega} = 1 flatness/inflation argument. It is shown that (1) the majority of baryons are dark; and (2) non-baryonic darkmatter is probably required on large scales. It is also noted that halo darkmatter could be either baryonic or non-baryonic. Descrimination between ``cold`` and ``hot`` non-baryonic candidates is shown to depend on the assumed ``seeds`` that stimulate structure formation. Gaussian density fluctuations, such as those induced by quantum fluctuations, favor cold darkmatter, whereas topological defects such as strings, textures or domain walls may work equally or better with hot darkmatter. A possible connection between cold darkmatter, globular cluster ages and the Hubble constant is mentioned. Recent large-scale structure measurements, coupled with microwave anisotropy limits, are shown to raise some questions for the previously favored density fluctuation picture. Accelerator and underground limits on darkmatter candidates are also reviewed.

The cosmological darkmatter problem is reviewed. The Big Bang Nucleosynthesis constraints on the baryon density are compared with the densities implied by visible matter, dark halos, dynamics of clusters, gravitational lenses, large-scale velocity flows, and the {Omega} = 1 flatness/inflation argument. It is shown that (1) the majority of baryons are dark; and (2) non-baryonic darkmatter is probably required on large scales. It is also noted that halo darkmatter could be either baryonic or non-baryonic. Descrimination between cold'' and hot'' non-baryonic candidates is shown to depend on the assumed seeds'' that stimulate structure formation. Gaussian density fluctuations, such as those induced by quantum fluctuations, favor cold darkmatter, whereas topological defects such as strings, textures or domain walls may work equally or better with hot darkmatter. A possible connection between cold darkmatter, globular cluster ages and the Hubble constant is mentioned. Recent large-scale structure measurements, coupled with microwave anisotropy limits, are shown to raise some questions for the previously favored density fluctuation picture. Accelerator and underground limits on darkmatter candidates are also reviewed.

The cosmological darkmatter problem is reviewed. The Big Bang Nucleosynthesis constraints on the baryon density are compared with the densities implied by visible matter, dark halos, dynamics of clusters, gravitational lenses, large-scale velocity flows, and the Ω = 1 flatness/inflation argument. It is shown that (1) the majority of baryons are dark; and (2) non-baryonic darkmatter is probably required on large scales. It is also noted that halo darkmatter could be either baryonic or non-baryonic. Descrimination between ''cold'' and ''hot'' non-baryonic candidates is shown to depend on the assumed ''seeds'' that stimulate structure formation. Gaussian density fluctuations, such as those induced by quantum fluctuations, favor cold darkmatter, whereas topological defects such as strings, textures or domain walls may work equally or better with hot darkmatter. A possible connection between cold darkmatter, globular cluster ages and the Hubble constant is mentioned. Recent large-scale structure measurements, coupled with microwave anisotropy limits, are shown to raise some questions for the previously favored density fluctuation picture. Accelerator and underground limits on darkmatter candidates are also reviewed

Supersymmetric models predict a natural dark-matter candidate, stable baryonic Q-balls. They could be copiously produced in the early Universe as a by-product of the Affleck-Dine baryogenesis. I review the cosmological and astrophysical implications, methods of detection, and the present limits on this form of darkmatter.

Reasons supporting the idea that most of the darkmatter in galaxies and clusters of galaxies is baryonic are discussed. Moreover, it is argued that most of the darkmatter in galactic halos should be in the form of MACHOs and cold molecular clouds.

We introduce a new paradigm for darkmatter (DM) interactions in which the interaction strength is asymptotically safe. In models of this type, the coupling strength is small at low energies but increases at higher energies, and asymptotically approaches a finite constant value. The resulting...... searches are the primary ways to constrain or discover asymptotically safe darkmatter....

We consider a simple class of models in which the relic density of darkmatter is determined by the baryon asymmetry of the Universe. In these models a B-L asymmetry generated at high temperatures is transferred to the darkmatter, which is charged under B-L. The interactions that transfer the asymmetry decouple at temperatures above the darkmatter mass, freezing in a darkmatter asymmetry of order the baryon asymmetry. This explains the observed relation between the baryon and darkmatter densities for the darkmatter mass in the range 5-15 GeV. The symmetric component of the darkmatter can annihilate efficiently to light pseudoscalar Higgs particles a or via t-channel exchange of new scalar doublets. The first possibility allows for h 0 →aa decays, while the second predicts a light charged Higgs-like scalar decaying to τν. Direct detection can arise from Higgs exchange in the first model or a nonzero magnetic moment in the second. In supersymmetric models, the would-be lightest supersymmetric partner can decay into pairs of darkmatter particles plus standard model particles, possibly with displaced vertices.

We have considered a model of Dark Minimal Flavour Violation (DMFV), in which a triplet of darkmatter particles couple to right-handed up-type quarks via a heavy colour-charged scalar mediator. By studying a large spectrum of possible constraints, and assessing the entire parameter space using a Markov Chain Monte Carlo (MCMC), we can place strong restrictions on the allowed parameter space for darkmatter models of this type.

Darkmatter is a vital component of the current best model of our universe, $\\Lambda$CDM. There are leading candidates for what the darkmatter could be (e.g. weakly-interacting massive particles, or axions), but no compelling observational or experimental evidence exists to support these particular candidates, nor any beyond-the-Standard-Model physics that might produce such candidates. This suggests that other darkmatter candidates, including ones that might arise in the Standard Model, should receive increased attention. Here we consider a general class of darkmatter candidates with characteristic masses and interaction cross-sections characterized in units of grams and cm$^2$, respectively -- we therefore dub these macroscopic objects as Macros. Such darkmatter candidates could potentially be assembled out of Standard Model particles (quarks and leptons) in the early universe. A combination of earth-based, astrophysical, and cosmological observations constrain a portion of the Macro parameter space; ho...

We explore a cosmological model composed by a darkmatter fluid interacting with a dark energy fluid. The interaction term has the non-linear λρ m α ρ e β form, where ρ m and ρ e are the energy densities of the darkmatter and dark energy, respectively. The parameters α and β are in principle not constrained to take any particular values, and were estimated from observations. We perform an analytical study of the evolution equations, finding the fixed points and their stability properties in order to characterize suitable physical regions in the phase space of the darkmatter and dark energy densities. The constants (λ,α,β) as well as w m and w e of the EoS of darkmatter and dark energy respectively, were estimated using the cosmological observations of the type Ia supernovae and the Hubble expansion rate H(z) data sets. We find that the best estimated values for the free parameters of the model correspond to a warm darkmatter interacting with a phantom dark energy component, with a well goodness-of-fit to data. However, using the Bayesian Information Criterion (BIC) we find that this model is overcame by a warm darkmatter – phantom dark energy model without interaction, as well as by the ΛCDM model. We find also a large dispersion on the best estimated values of the (λ,α,β) parameters, so even if we are not able to set strong constraints on their values, given the goodness-of-fit to data of the model, we find that a large variety of theirs values are well compatible with the observational data used

We propose a novel mechanism for darkmatter to explain the observed annual modulation signal at DAMA/LIBRA which avoids existing constraints from every other darkmatter direct detection experiment including CRESST, CDMS, and XENON10. The darkmatter consists of at least two light states with mass ∼few GeV and splittings ∼5 keV. It is natural for the heavier states to be cosmologically long-lived and to make up an O(1) fraction of the darkmatter. Direct detection rates are dominated by the exothermic reactions in which an excited darkmatter state downscatters off of a nucleus, becoming a lower energy state. In contrast to (endothermic) inelastic darkmatter, the most sensitive experiments for exothermic darkmatter are those with light nuclei and low threshold energies. Interestingly, this model can also naturally account for the observed low-energy events at CoGeNT. The only significant constraint on the model arises from the DAMA/LIBRA unmodulated spectrum but it can be tested in the near future by a low-threshold analysis of CDMS-Si and possibly other experiments including CRESST, COUPP, and XENON100.

We construct an explicit, TeV-scale model of decaying darkmatter in which the approximate stability of the darkmatter candidate is a consequence of a global symmetry that is broken only by instanton-induced operators generated by a non-Abelian dark gauge group. The dominant darkmatter decay channels are to standard model leptons. Annihilation of the darkmatter to standard model states occurs primarily through the Higgs portal. We show that the mass and lifetime of the darkmatter candidate in this model can be chosen to be consistent with the values favored by fits to data from the PAMELA and Fermi-LAT experiments.

The identification of darkmatter is one of the most urgent problems in cosmology. I describe the astrophysical case for darkmatter, from both an observational and a theoretical perspective. This overview will therefore focus on the observational motivations rather than the particle physics aspects of darkmatter constraints on specific darkmatter candidates. First, however, I summarize the astronomical evidence for darkmatter, then I highlight the weaknesses of the standard cold darkmatter model (LCDM) to provide a robust explanation of some observations. The greatest weakness in the darkmatter saga is that we have not yet identified the nature of darkmatter itself

Many observations suggest that much of the matter of the universe is nonbaryonic. Recently, the DAMA NaI darkmatter direct detection experiment reported an annual modulation in their event rate consistent with a WIMP relic. However, the Cryogenic DarkMatter Search (CDMS) Ge experiment excludes most of the region preferred by DAMA. We demonstrate that if the darkmatter can only scatter by making a transition to a slightly heavier state (Δm∼100 keV), the experiments are no longer in conflict. Moreover, differences in the energy spectrum of nuclear recoil events could distinguish such a scenario from the standard WIMP scenario. Finally, we discuss the sneutrino as a candidate for inelastic darkmatter in supersymmetric theories

Many searches for baryonic darkmatter have been conducted but, so far, all have been unsuccessful. Indeed, no more than 1% of the darkmatter can be in the form of hydrogen burning stars. It has recently been suggested that most of the baryons in the universe are still in the form of ionized gas so that it is possible that there is no baryonic darkmatter. Although it is likely that a significant fraction of the darkmatter in the Milky Way is in a halo of non-baryonic matter, the data do not exclude the possibility that a considerable amount, perhaps most of it, could be in a tenuous halo of diffuse ionized gas

Most of the mass in the universe is in the form of darkmatter--a new type of nonbaryonic particle not yet detected in the laboratory or in other detection experiments. The evidence for the existence of darkmatter through its gravitational impact is clear in astronomical observations--from the early observations of the large motions of galaxies in clusters and the motions of stars and gas in galaxies, to observations of the large-scale structure in the universe, gravitational lensing, and the cosmic microwave background. The extensive data consistently show the dominance of darkmatter and quantify its amount and distribution, assuming general relativity is valid. The data inform us that the darkmatter is nonbaryonic, is "cold" (i.e., moves nonrelativistically in the early universe), and interacts only weakly with matter other than by gravity. The current Lambda cold darkmatter cosmology--a simple (but strange) flat cold darkmatter model dominated by a cosmological constant Lambda, with only six basic parameters (including the density of matter and of baryons, the initial mass fluctuations amplitude and its scale dependence, and the age of the universe and of the first stars)--fits remarkably well all the accumulated data. However, what is the darkmatter? This is one of the most fundamental open questions in cosmology and particle physics. Its existence requires an extension of our current understanding of particle physics or otherwise point to a modification of gravity on cosmological scales. The exploration and ultimate detection of darkmatter are led by experiments for direct and indirect detection of this yet mysterious particle.

Full Text Available We consider a resonant SIMP darkmatter in models with two singlet complex scalar fields charged under a local dark U(1D. After the U(1D is broken down to a Z5 discrete subgroup, the lighter scalar field becomes a SIMP darkmatter which has the enhanced 3→2 annihilation cross section near the resonance of the heavier scalar field. Bounds on the SIMP self-scattering cross section and the relic density can be fulfilled at the same time for perturbative couplings of SIMP. A small gauge kinetic mixing between the SM hypercharge and dark gauge bosons can be used to make SIMP darkmatter in kinetic equilibrium with the SM during freeze-out.

Most of the mass in the universe is in the form of dark matter—a new type of nonbaryonic particle not yet detected in the laboratory or in other detection experiments. The evidence for the existence of darkmatter through its gravitational impact is clear in astronomical observations—from the early observations of the large motions of galaxies in clusters and the motions of stars and gas in galaxies, to observations of the large-scale structure in the universe, gravitational lensing, and the cosmic microwave background. The extensive data consistently show the dominance of darkmatter and quantify its amount and distribution, assuming general relativity is valid. The data inform us that the darkmatter is nonbaryonic, is “cold” (i.e., moves nonrelativistically in the early universe), and interacts only weakly with matter other than by gravity. The current Lambda cold darkmatter cosmology—a simple (but strange) flat cold darkmatter model dominated by a cosmological constant Lambda, with only six basic parameters (including the density of matter and of baryons, the initial mass fluctuations amplitude and its scale dependence, and the age of the universe and of the first stars)—fits remarkably well all the accumulated data. However, what is the darkmatter? This is one of the most fundamental open questions in cosmology and particle physics. Its existence requires an extension of our current understanding of particle physics or otherwise point to a modification of gravity on cosmological scales. The exploration and ultimate detection of darkmatter are led by experiments for direct and indirect detection of this yet mysterious particle. PMID:26417091

We examine the darkmatter phenomenology of a composite electroweak singlet state. This singlet belongs to the Goldstone sector of a well-motivated extension of the Littlest Higgs with T -parity. A viable parameter space, consistent with the observed darkmatter relic abundance as well as with the various collider, electroweak precision and darkmatter direct detection experimental constraints is found for this scenario. T -parity implies a rich LHC phenomenology, which forms an interesting interplay between conventional natural SUSY type of signals involving third generation quarks and missing energy, from stop-like particle production and decay, and composite Higgs type of signals involving third generation quarks associated with Higgs and electroweak gauge boson, from vector-like top-partners production and decay. The composite features of the darkmatter phenomenology allows the composite singlet to produce the correct relic abundance while interacting weakly with the Higgs via the usual Higgs portal coupling [Formula: see text], thus evading direct detection.

We describe a general scenario, dubbed "inflatable darkmatter," in which the density of darkmatter particles can be reduced through a short period of late-time inflation in the early Universe. The overproduction of darkmatter that is predicted within many, otherwise, well-motivated models of new physics can be elegantly remedied within this context. Thermal relics that would, otherwise, be disfavored can easily be accommodated within this class of scenarios, including darkmatter candidates that are very heavy or very light. Furthermore, the nonthermal abundance of grand unified theory or Planck scale axions can be brought to acceptable levels without invoking anthropic tuning of initial conditions. A period of late-time inflation could have occurred over a wide range of scales from ∼MeV to the weak scale or above, and could have been triggered by physics within a hidden sector, with small but not necessarily negligible couplings to the standard model.

Some general arguments on the particle DarkMatter search are addressed. The WIMP direct detection technique is mainly considered and recent results obtained by exploiting the annual modulation signature are summarized. (author)

These lectures concentrate on evolution and generation of darkmatter perturbations. The purpose of the lectures is to present, in a systematic way, a comprehensive review of the cosmological parameters that can lead to observable effects in the darkmatter clustering properties. We begin by reviewing the relativistic linear perturbation theory formalism. We discuss the gauge issue and derive Einstein's and continuity equations for several popular gauge choices. We continue by developing fluid equations for cold darkmatter and baryons and Boltzmann equations for photons, massive and massless neutrinos. We then discuss the generation of initial perturbations by the process of inflation and the parameters of that process that can be extracted from the observations. Finally we discuss evolution of perturbations in various regimes and the imprint of the evolution on the darkmatter power spectrum both in the linear and in the nonlinear regime. (author)

These lectures concentrate on evolution and generation of darkmatter perturbations. The purpose of the lectures is to present, in a systematic way, a comprehensive review of the cosmological parameters that can lead to observable effects in the darkmatter clustering properties. We begin by reviewing the relativistic linear perturbation theory formalism. We discuss the gauge issue and derive Einstein's and continuity equations for several popular gauge choices. We continue by developing fluid equations for cold darkmatter and baryons and Boltzmann equations for photons, massive and massless neutrinos. We then discuss the generation of initial perturbations by the process of inflation and the parameters of that process that can be extracted from the observations. Finally we discuss evolution of perturbations in various regimes and the imprint of the evolution on the darkmatter power spectrum both in the linear and in the nonlinear regime. (author)

Some general arguments on the particle DarkMatter search are addressed. The WIMP direct detection technique is mainly considered and recent results obtained by exploiting the annual modulation signature are summarized. (author)

The quest for the mysterious missing mass of the universe has become one of the big challenges of today's particle physics and cosmology. Astronomical observations show that only 1% of the matter of the universe is luminous. Moreover there is now convincing evidence that 85% of all gravitationally observable matter in the universe is of a new exotic kind, different from the 'ordinary' matter surrounding us. In a series of three lectures we discuss past, recent and future efforts made world-wide to detect and/or decipher the nature of DarkMatter. In Lecture I we review our present knowledge of the DarkMatter content of the Universe and how experimenters search for it's candidates; In Lecture II we discuss so-called 'direct detection' techniques which allow to search for scattering of galactic darkmatter particles with detectors in deep-underground laboratories; we discuss the interpretation of experimental results and the challenges posed by different backgrounds; In Lecture III we take a look at the 'indirect detection' of the annihilation of darkmatter candidates in astrophysical objects, such as our sun or the center of the Milky Way; In addition we will have a look at efforts to produce DarkMatter particles directly at accelerators and we shall close with a look at alternative nonparticle searches and future prospects. (author)

The quest for the mysterious missing mass of the universe has become one of the big challenges of today's particle physics and cosmology. Astronomical observations show that only 1% of the matter of the universe is luminous. Moreover there is now convincing evidence that 85% of all gravitationally observable matter in the universe is of a new exotic kind, different from the 'ordinary' matter surrounding us. In a series of three lectures we discuss past, recent and future efforts made world-wide to detect and/or decipher the nature of DarkMatter. In Lecture I we review our present knowledge of the DarkMatter content of the Universe and how experimenters search for it's candidates; In Lecture II we discuss so-called 'direct detection' techniques which allow to search for scattering of galactic darkmatter particles with detectors in deep-underground laboratories; we discuss the interpretation of experimental results and the challenges posed by different backgrounds; In Lecture III we take a look at the 'indirect detection' of the annihilation of darkmatter candidates in astrophysical objects, such as our sun or the center of the Milky Way; In addition we will have a look at efforts to produce DarkMatter particles directly at accelerators and we shall close with a look at alternative nonparticle searches and future prospects. (author)

The quest for the missing mass of the universe has become one of the big challenges of todays particle physics and cosmology. Astronomical observations show that only 1% of the matter of the Universe is luminous. Moreover there is now convincing evidence that 85% of all gravitationally observable matter in the Universe is of a new exotic kind, different from the 'ordinary' matter surrounding us. In a series of three lectures we discuss past, recent and future efforts made world- wide to detect and/or decipher the nature of DarkMatter. In Lecture I we review our present knowledge of the DarkMatter content of the Universe and how experimenters search for it's candidates; In Lecture II we discuss so-called 'direct detection' techniques which allow to search for scattering of galactic darkmatter particles with detectors in deep-underground laboratories; we discuss the interpretation of experimental results and the challenges posed by different backgrounds; In Lecture III we take a look at the 'indirect detection' of the annihilation of darkmatter candidates in astrophysical objects, such as our sun or the center of the Milky Way; In addition we will have a look at efforts to produce DarkMatter particles directly at accelerators and we shall close with a look at alternative nonparticle searches and future prospects. (author)

The author both reviews and makes the case for the current theoretical prejudice: a flat Universe whose dominant constituent is nonbaryonic darkmatter, emphasizing that this is still a prejudice and not yet fact. The theoretical motivation for nonbaryonic darkmatter is discussed in the context of current elementary-particle theory, stressing that (i) there are no dark-matter candidates within the open-quotes standard modelclose quotes of particle physics, (ii) there are several compelling candidates within attractive extensions of the standard model of particle physics, and (iii) the motivation for these compelling candidates comes first and foremost from particle physics. The dark-matter problem is now a pressing issue in both cosmology and particle physics, and the detection of particle darkmatter would provide evidence for open-quotes new physics.close quotes The compelling candidates are a very light axion (10 -6 --10 -4 eV), a light neutrino (20--90 eV), and a heavy neutralino (10 GeV--2 TeV). The production of these particles in the early Universe and the prospects for their detection are also discussed. The author briefly mentions more exotic possibilities for the darkmatter, including a nonzero cosmological constant, superheavy magnetic monopoles, and decaying neutrinos. 119 refs

I both review and make the case for the current theoretical prejudice: a flat Universe whose dominant constituent is nonbaryonic darkmatter, emphasizing that this is still a prejudice and not yet fact. The theoretical motivation for nonbaryonic darkmatter is discussed in the context of current elementary-particle theory, stressing that: (1) there are no darkmatter candidates within the standard model of particle physics; (2) there are several compelling candidates within attractive extensions of the standard model of particle physics; and (3) the motivation for these compelling candidates comes first and foremost from particle physics. The dark-matter problem is now a pressing issue in both cosmology and particle physics, and the detection of particle darkmatter would provide evidence for ''new physics.'' The compelling candidates are: a very light axion ( 10 -6 eV--10 -4 eV); a light neutrino (20 eV--90 eV); and a heavy neutralino (10 GeV--2 TeV). The production of these particles in the early Universe and the prospects for their detection are also discussed. I briefly mention more exotic possibilities for the darkmatter, including a nonzero cosmological constant, superheavy magnetic monopoles, and decaying neutrinos

I both review and make the case for the current theoretical prejudice: a flat Universe whose dominant constituent is nonbaryonic darkmatter, emphasizing that this is still a prejudice and not yet fact. The theoretical motivation for nonbaryonic darkmatter is discussed in the context of current elementary-particle theory, stressing that: (1) there are no darkmatter candidates within the standard model of particle physics; (2) there are several compelling candidates within attractive extensions of the standard model of particle physics; and (3) the motivation for these compelling candidates comes first and foremost from particle physics. The dark-matter problem is now a pressing issue in both cosmology and particle physics, and the detection of particle darkmatter would provide evidence for new physics.'' The compelling candidates are: a very light axion ( 10[sup [minus]6] eV--10[sup [minus]4] eV); a light neutrino (20 eV--90 eV); and a heavy neutralino (10 GeV--2 TeV). The production of these particles in the early Universe and the prospects for their detection are also discussed. I briefly mention more exotic possibilities for the darkmatter, including a nonzero cosmological constant, superheavy magnetic monopoles, and decaying neutrinos.

I both review and make the case for the current theoretical prejudice: a flat Universe whose dominant constituent is nonbaryonic darkmatter, emphasizing that this is still a prejudice and not yet fact. The theoretical motivation for nonbaryonic darkmatter is discussed in the context of current elementary-particle theory, stressing that: (1) there are no darkmatter candidates within the standard model of particle physics; (2) there are several compelling candidates within attractive extensions of the standard model of particle physics; and (3) the motivation for these compelling candidates comes first and foremost from particle physics. The dark-matter problem is now a pressing issue in both cosmology and particle physics, and the detection of particle darkmatter would provide evidence for ``new physics.`` The compelling candidates are: a very light axion ( 10{sup {minus}6} eV--10{sup {minus}4} eV); a light neutrino (20 eV--90 eV); and a heavy neutralino (10 GeV--2 TeV). The production of these particles in the early Universe and the prospects for their detection are also discussed. I briefly mention more exotic possibilities for the darkmatter, including a nonzero cosmological constant, superheavy magnetic monopoles, and decaying neutrinos.

Very weakly interacting slim particles (WISPs), such as axion-like particles (ALPs) or hidden photons (HPs), may be non-thermally produced via the misalignment mechanism in the early universe and survive as a cold darkmatter population until today. We find that, both for ALPs and HPs whose dominant interactions with the standard model arise from couplings to photons, a huge region in the parameter spaces spanned by photon coupling and ALP or HP mass can give rise to the observed cold darkmatter. Remarkably, a large region of this parameter space coincides with that predicted in well motivated models of fundamental physics. A wide range of experimental searches - exploiting haloscopes (direct darkmatter searches exploiting microwave cavities), helioscopes (searches for solar ALPs or HPs), or light-shining-through-a-wall techniques - can probe large parts of this parameter space in the foreseeable future. (orig.)

In the supersymmetric framework, prior to the electroweak phase transition, the existence of a baryon asymmetry implies the existence of a Higgsino asymmetry. We investigate whether the Higgsino could be a viable asymmetric darkmatter candidate. We find that this is indeed possible. Thus, supersymmetry can provide the observed darkmatter abundance and, furthermore, relate it with the baryon asymmetry, in which case the puzzle of why the baryonic and darkmatter mass densities are similar would be explained. To accomplish this task, two conditions are required. First, the gauginos, squarks, and sleptons must all be very heavy, such that the only electroweak-scale superpartners are the Higgsinos. With this spectrum, supersymmetry does not solve the fine-tuning problem. Second, the temperature of the electroweak phase transition must be low, in the (1-10) GeV range. This condition requires an extension of the minimal supersymmetric standard model.

According to the standard cosmological model, 95% of the present mass density of the universe is dark: roughly 70% of the total in the form of dark energy and 25% in the form of darkmatter. In a series of four lectures, I will begin by presenting a brief review of cosmology, and then I will review the observational evidence for darkmatter and dark energy. I will discuss some of the proposals for darkmatter and dark energy, and connect them to high-energy physics. I will also present an overview of an observational program to quantify the properties of dark energy.

The first stars to form in the Universe may be powered by the annihilation of weakly interacting darkmatter particles. These so-called dark stars, if observed, may give us a clue about the nature of darkmatter. Here we examine which models for particle darkmatter satisfy the conditions for the formation of dark stars. We find that in general models with thermal darkmatter lead to the formation of dark stars, with few notable exceptions: heavy neutralinos in the presence of coannihilations, annihilations that are resonant at darkmatter freeze-out but not in dark stars, some models of neutrinophilic darkmatter annihilating into neutrinos only and lighter than about 50 GeV. In particular, we find that a thermal DM candidate in standard Cosmology always forms a dark star as long as its mass is heavier than ≅ 50 GeV and the thermal average of its annihilation cross section is the same at the decoupling temperature and during the dark star formation, as for instance in the case of an annihilation cross section with a non-vanishing s-wave contribution

We explore the viability of a boson darkmatter candidate with an asymmetry between the number densities of particles and antiparticles. A simple thermal field theory analysis confirms that, under certain general conditions, this component would develop a Bose-Einstein condensate in the early universe that, for appropriate model parameters, could survive the ensuing cosmological evolution until now. The condensation of a darkmatter component in equilibrium with the thermal plasma is a relativistic process, hence the amount of matter dictated by the charge asymmetry is complemented by a hot relic density frozen out at the time of decoupling. Contrary to the case of ordinary WIMPs, darkmatter particles in a condensate must be lighter than a few tens of eV so that the density from thermal relics is not too large. Big-Bang nucleosynthesis constrains the temperature of decoupling to the scale of the QCD phase transition or above. This requires large darkmatter-to-photon ratios and very weak interactions with standard model particles.

We first explain the concept of darkmatter,then review the history of its discovery and the evidence of its existence. We describe our understanding of the nature of darkmatter particles, the popular darkmatter models,and why the weakly interacting massive particles (called WIMPs) are the most attractive candidates for darkmatter. Then we introduce the three methods of darkmatter detection: colliders, direct detection and indirect detection. Finally, we review the recent development of darkmatter detection, including the new results from DAMA, CoGent, PAMELA, ATIC and Fermi. (authors)

Evidence for darkmatter continues to build up. Last year (December 1993, page 4) excitement rose when the French EROS (Experience de Recherche d'Objets Sombres) and the US/Australia MACHO collaborations reported hints that small inert 'brown dwarf stars could provide some of the Universe's missing matter. In the 1930s, astronomers first began to suspect that there is a lot more to the Universe than meets the eye

We examine the darkmatter phenomenology of a composite electroweak singlet state. This singlet belongs to the Goldstone sector of a well-motivated extension of the Littlest Higgs with T-parity. A viable parameter space, consistent with the observed darkmatter relic abundance as well as with the various collider, electroweak precision and darkmatter direct detection experimental constraints is found for this scenario. T-parity implies a rich LHC phenomenology, which forms an interesting interplay between conventional natural SUSY type of signals involving third generation quarks and missing energy, from stop-like particle production and decay, and composite Higgs type of signals involving third generation quarks associated with Higgs and electroweak gauge boson, from vector-like top-partners production and decay. The composite features of the darkmatter phenomenology allows the composite singlet to produce the correct relic abundance while interacting weakly with the Higgs via the usual Higgs portal coupling λ _{ {DM}}˜ O(1%), thus evading direct detection.

I review the construction of Simplified Models for DarkMatter searches. After discussing the philosophy and some simple examples, I turn the attention to the aspect of the theoretical consistency and to the implications of the necessary extensions of these models.

We present a non perturbative study of SU(2) gauge theory with two fundamental Dirac flavours. We discuss how the model can be used as a template for composite DarkMatter (DM). We estimate one particular interaction of the DM candidate with the Standard Model : the interaction through photon...

We examine the darkmatter phenomenology of a composite electroweak singlet state. This singlet belongs to the Goldstone sector of a well-motivated extension of the Littlest Higgs with T-parity. A viable parameter space, consistent with the observed darkmatter relic abundance as well as with the various collider, electroweak precision and darkmatter direct detection experimental constraints is found for this scenario. T-parity implies a rich LHC phenomenology, which forms an interesting interplay between conventional natural SUSY type of signals involving third generation quarks and missing energy, from stop-like particle production and decay, and composite Higgs type of signals involving third generation quarks associated with Higgs and electroweak gauge boson, from vector-like top-partners production and decay. The composite features of the darkmatter phenomenology allows the composite singlet to produce the correct relic abundance while interacting weakly with the Higgs via the usual Higgs portal coupling λ{sub DM} ∝ O(1%), thus evading direct detection. (orig.)

This report discusses why axions have been postulated to exist, what cosmology implies about their presence as cold darkmatter in the galactic halo, how axions might be detected in cavities wherein strong magnetic fields stimulate their conversion into photons, and relations between axions' energy spectra and galactic halos' properties

We explore some of the consequences of dark-matter-photon interactions on structure formation, focusing on the evolution of cosmological perturbations and performing both an analytical and a numerical study. We compute the cosmic microwave background anisotropies and matter power spectrum in this class of models. We find, as the main result, that when darkmatter and photons are coupled, darkmatter perturbations can experience a new damping regime in addition to the usual collisional Silk damping effect. Such darkmatter particles (having quite large photon interactions) behave like cold darkmatter or warm darkmatter as far as the cosmic microwave background anisotropies or matter power spectrum are concerned, respectively. These dark-matter-photon interactions leave specific imprints at sufficiently small scales on both of these two spectra, which may allow us to put new constraints on the acceptable photon-dark-matter interactions. Under the conservative assumption that the abundance of 10 12 M · galaxies is correctly given by the cold darkmatter, and without any knowledge of the abundance of smaller objects, we obtain the limit on the ratio of the dark-matter-photon cross section to the darkmatter mass σ γ-DM /m DM -6 σ Th /(100 GeV)≅6x10 -33 cm 2 GeV -1

We consider a minimal extension of the Standard Model (SM), which leads to unification of the SM coupling constants, breaks electroweak symmetry dynamically by a new strongly coupled sector and leads to novel darkmatter candidates. In this model, the coupling constant unification requires...... eigenstates of this sector and determine the resulting relic density. The results are constrained by available data from colliders and direct and indirect darkmatter experiments. We find the model viable and outline briefly future research directions....... the existence of electroweak triplet and doublet fermions singlet under QCD and new strong dynamics underlying the Higgs sector. Among these new matter fields and a new right handed neutrino, we consider the mass and mixing patterns of the neutral states. We argue for a symmetry stabilizing the lightest mass...

We discuss the viability of a light particle (∼30eV neutrino) with strong self-interactions as a darkmatter candidate. The interaction prevents the neutrinos from free-streaming during the radiation-dominated regime so galaxy-sized density perturbations can survive. Smaller scale perturbations are damped due to neutrino diffusion. We calculate the power spectrum in the imperfect fluid approximation, and show that it is damped at the length scale one would estimate due to neutrino diffusion. The strength of the neutrino-neutrino coupling is only weakly constrained by observations, and could be chosen by fitting the power spectrum to the observed amplitude of matter density perturbations. The main shortcoming of our model is that interacting neutrinos cannot provide the darkmatter in dwarf galaxies. copyright 1997 The American Physical Society

This article discusses the nature of the darkmatter and the possibility of the detection of non-baryonic darkmatter in an underground experiment. Among the useful detectors the low temperature bolometers are considered in some detail. (author)

A sizable fraction of the total energy density of the universe may be in heavy particles with a net dark U(1)' charge comparable to its mass. When the charges have the same sign the cancellation between their gravitational and gauge forces may lead to a mismatch between different measures of masses in the universe. Measuring galactic masses by orbits of normal matter, such as galaxy rotation curves or lensing, will give the total mass, while the flows of darkmatter agglomerates may yield smaller values if the gauge repulsion is not accounted for. If distant galaxies which house light beacons like SNe Ia contain such dark particles, the observations of their cosmic recession may mistake the weaker forces for an extra 'antigravity', and infer an effective dark energy equation of state smaller than the real one. In some cases, including that of a cosmological constant, these effects can mimic w < −1. They can also lead to a local variation of galaxy-galaxy forces, yielding a larger 'Hubble Flow' in those regions of space that could be taken for a dynamical dark energy, or superhorizon effects.

A sizable fraction of the total energy density of the universe may be in heavy particles with a net dark U(1)' charge comparable to its mass. When the charges have the same sign the cancellation between their gravitational and gauge forces may lead to a mismatch between different measures of masses in the universe. Measuring galactic masses by orbits of normal matter, such as galaxy rotation curves or lensing, will give the total mass, while the flows of darkmatter agglomerates may yield smaller values if the gauge repulsion is not accounted for. If distant galaxies which house light beacons like SNe Ia contain such dark particles, the observations of their cosmic recession may mistake the weaker forces for an extra `antigravity', and infer an effective dark energy equation of state smaller than the real one. In some cases, including that of a cosmological constant, these effects can mimic w < -1. They can also lead to a local variation of galaxy-galaxy forces, yielding a larger `Hubble Flow' in those regions of space that could be taken for a dynamical dark energy, or superhorizon effects.

Darkmatter in the Universe is likely to be made up of some new, hypothetical particle which would be a part of an extension of the Standard Model of particle physics. In this overview, I will first briefly review well motivated particle candidates for darkmatter. Next I will focus my attention on the neutralino of supersymmetry which is the by far most popular darkmatter candidate. I will discuss some recent progress and comment on prospects for darkmatter detection.

This lecture course covers cosmology from the particle physicist perspective. Therefore, the emphasis will be on the evidence for the new physics in cosmological and astrophysical data together with minimal theoretical frameworks needed to understand and appreciate the evidence. I review the case for non-baryonic darkmatter and describe popular models which incorporate it. In parallel, the story of dark energy will be developed, which includes accelerated expansion of the Universe today, the Universe origin in the Big Bang, and support for the Inflationary theory in CMBR data.

This talk will present darkmatter searches at the LHC in the PIC2017 conference. The main emphasis is placed on the direct darkmatter searches while the interpretation of searches for SUSY and invisible Higgs signals for the darkmatter is also presented.

In this non-specialist review I look at how weak lensing can provide information on the dark sector of the Universe. The review concentrates on what can be learned about DarkMatter, Dark Energy and Dark Gravity, and why. On DarkMatter, results on the confrontation of theoretical profiles with observation are reviewed, and measurements of neutrino masses discussed. On Dark Energy, the interest is whether this could be Einstein's cosmological constant, and prospects for high-precision studies of the equation of state are considered. On Dark Gravity, we consider the exciting prospects for future weak lensing surveys to distinguish General Relativity from extra-dimensional or other gravity theories.

We study candidates for darkmatter in a minimal flipped SU(5) x U(1) supersymmetric GUT. Since the model has no R-parity, spin-1/2 supersymmetric partners of conventional particles mix with other neutral fermions including neutrinos, and can decay into them. The lighest particle which is predominantly a gaugino/higgsino mixture decays with a lifetime tau/sub chi/ approx. = 1-10/sup 9/ s. The model contains a scalar 'flaton' field whose coherent oscillations decay before cosmological nucleosynthesis, and whose pseudoscalar partner contributes negligibly to ..cap omega.. if it is light enough to survive to the present epoch. The fermionic 'flatino' partner of the flaton has a lifetime tau/sub PHI/ approx. = 10/sup 28/-10/sup 34/ yr and is a viable candiate for metastable darkmatter with ..cap omega.. < or approx. 1.

One of the simplest, yet most profound, questions we can ask about the Universe is, how much stuff is in it, and further what is that stuff composed of? Needless to say, the answer to this question has very important implications for the evolution of the Universe, determining both the ultimate fate and the course of structure formation. Remarkably, at this late date in the history of the Universe we still do not have a definitive answer to this simplest of questions---although we have some very intriguing clues. It is known with certainty that most of the material in the Universe is dark, and we have the strong suspicion that the dominant component of material in the Cosmos is not baryons, but rather is exotic relic elementary particles left over from the earliest, very hot epoch of the Universe. If true, the DarkMatter question is a most fundamental one facing both particle physics and cosmology. The leading particle darkmatter candidates are: the axion, the neutralino, and a light neutrino species. All three candidates are accessible to experimental tests, and experiments are now in progress. In addition, there are several dark horse, long shot, candidates, including the superheavy magnetic monopole and soliton stars. 13 refs

Both canonical primordial nucleosynthesis constraints and large-scale structure measurements, as well as observations of the fundamental cosmological parameters, appear to be consistent with the hypothesis that the universe predominantly consists of baryonic darkmatter (BDM). The arguments for BDM to consist of compact objects that are either stellar relics or substellar objects are reviewed. Several techniques for searching for halo BDM are described.

Until recently little more was known than that darkmatter appears to exist; there was little systematic information about its properties. Only in the past several years was progress made to the point where darkmatter density distributions can be measured. For example, with accurate rotation curves extending over large ranges in radius, decomposing the effects of visible and darkmatter to measure darkmatter density profiles can be tried. Some regularities in darkmatter behaviour have already turned up. This volume includes review and invited papers, poster papers, and the two general discussions. (Auth.)

Overwhelming observational evidence indicates that most of the matter in the Universe consists of non-baryonic darkmatter. One possibility is that the darkmatter is Weakly-Interacting Massive Particles (WIMPs) that were produced in the early Universe. These relics could comprise the Milky Way's dark halo and provide evidence for new particle physics, such as Supersymmetry. This talk focuses on the status of current efforts to detect darkmatter by testing the hypothesis that WIMPs exist in the galactic halo. WIMP searches have begun to explore the region of parameter space where SUSY particles could provide darkmatter candidates.

One of the main purposes of physics at the International Linear Collider (ILC) is to study the property of darkmatter such as its mass, spin, quantum numbers, and interactions with particles of the standard model. We discuss how the property can or cannot be investigated at the ILC using two typical cases of darkmatter scenario: 1) most of new particles predicted in physics beyond the standard model are heavy and only darkmatter is accessible at the ILC, and 2) not only darkmatter but also other new particles are accessible at the ILC. We find that, as can be easily imagined, darkmatter can be detected without any difficulties in the latter case. In the former case, it is still possible to detect darkmatter when the mass of darkmatter is less than a half mass of the Higgs boson.

Darkmatter is hypothetical matter which does not interact with electromagnetic radiation. The existence of darkmatter is only inferred from gravitational effects of astrophysical observations to explain the missing mass component of the Universe. Weakly Interacting Massive Particles are currently the most popular candidate to explain the missing mass component. I review the current status of experimental searches of darkmatter through direct detection using terrestrial detectors.

It is one of the hidden secrets that literally surround the Universe. Experiments have shown no result so far because trying to capture particles that do not seem to interact with ordinary matter is no trivial exercise. The OSQAR experiment at CERN is dedicated to the search for axions, one of the candidates for DarkMatter. For its difficult challenge, OSQAR counts on one of the world’s most powerful magnets borrowed from the LHC. In a recent publication, the OSQAR collaboration was able to confirm that no axion signal appears out of the background. In other words: the quest is still on. The OSQAR experiment installed in the SM18 hall. (Photo by F. Capello) The OSQAR “Light Shining Through a Wall” experiment was officially launched in 2007 with the aim of detecting axions, that is, particles that might be the main components of DarkMatter. OSQAR uses the powerful LHC dipole magnet to intensify the predicted photon-axion conversions in the presence of strong m...

We propose a new motivation for the stability of darkmatter (DM). We suggest that the same non-abelian discrete flavor symmetry which accounts for the observed pattern of neutrino oscillations, spontaneously breaks to a Z2 subgroup which renders DM stable. The simplest scheme leads to a scalar doublet DM potentially detectable in nuclear recoil experiments, inverse neutrino mass hierarchy, hence a neutrinoless double beta decay rate accessible to upcoming searches, while reactor angle equal to zero gives no CP violation in neutrino oscillations.

We consider cosmology of the recently introduced mimetic matter with higher derivatives (HD). Without HD this system describes irrotational dust—DarkMatter (DM) as we see it on cosmologically large scales. DM particles correspond to the shift-charges—Noether charges of the shifts in the field space. Higher derivative corrections usually describe a deviation from the thermodynamical equilibrium in the relativistic hydrodynamics. Thus we show that mimetic matter with HD corresponds to an imperfect DM which: i) renormalises the Newton's constant in the Friedmann equations, ii) has zero pressure when there is no extra matter in the universe, iii) survives the inflationary expansion which puts the system on a dynamical attractor with a vanishing shift-charge, iv) perfectly tracks any external matter on this attractor, v) can become the main (and possibly the only) source of DM, provided the shift-symmetry in the HD terms is broken during some small time interval in the radiation domination époque. In the second part of the paper we present a hydrodynamical description of general anisotropic and inhomogeneous configurations of the system. This imperfect mimetic fluid has an energy flow in the field's rest frame. We find that in the Eckart and in the Landau-Lifshitz frames the mimetic fluid possesses nonvanishing vorticity appearing already at the first order in the HD. Thus, the structure formation and gravitational collapse should proceed in a rather different fashion from the simple irrotational DM models.

We consider cosmology of the recently introduced mimetic matter with higher derivatives (HD). Without HD this system describes irrotational dust—DarkMatter (DM) as we see it on cosmologically large scales. DM particles correspond to the shift-charges—Noether charges of the shifts in the field space. Higher derivative corrections usually describe a deviation from the thermodynamical equilibrium in the relativistic hydrodynamics. Thus we show that mimetic matter with HD corresponds to an imperfect DM which: i) renormalises the Newton's constant in the Friedmann equations, ii) has zero pressure when there is no extra matter in the universe, iii) survives the inflationary expansion which puts the system on a dynamical attractor with a vanishing shift-charge, iv) perfectly tracks any external matter on this attractor, v) can become the main (and possibly the only) source of DM, provided the shift-symmetry in the HD terms is broken during some small time interval in the radiation domination époque. In the second part of the paper we present a hydrodynamical description of general anisotropic and inhomogeneous configurations of the system. This imperfect mimetic fluid has an energy flow in the field's rest frame. We find that in the Eckart and in the Landau-Lifshitz frames the mimetic fluid possesses nonvanishing vorticity appearing already at the first order in the HD. Thus, the structure formation and gravitational collapse should proceed in a rather different fashion from the simple irrotational DM models

We consider cosmology of the recently introduced mimetic matter with higher derivatives (HD). Without HD this system describes irrotational dust—DarkMatter (DM) as we see it on cosmologically large scales. DM particles correspond to the shift-charges—Noether charges of the shifts in the field space. Higher derivative corrections usually describe a deviation from the thermodynamical equilibrium in the relativistic hydrodynamics. Thus we show that mimetic matter with HD corresponds to an imperfect DM which: i) renormalises the Newton's constant in the Friedmann equations, ii) has zero pressure when there is no extra matter in the universe, iii) survives the inflationary expansion which puts the system on a dynamical attractor with a vanishing shift-charge, iv) perfectly tracks any external matter on this attractor, v) can become the main (and possibly the only) source of DM, provided the shift-symmetry in the HD terms is broken during some small time interval in the radiation domination époque. In the second part of the paper we present a hydrodynamical description of general anisotropic and inhomogeneous configurations of the system. This imperfect mimetic fluid has an energy flow in the field's rest frame. We find that in the Eckart and in the Landau-Lifshitz frames the mimetic fluid possesses nonvanishing vorticity appearing already at the first order in the HD. Thus, the structure formation and gravitational collapse should proceed in a rather different fashion from the simple irrotational DM models.

The DarkSide staged program utilizes a two-phase time projection chamber (TPC) with liquid argon as the target material for the scattering of darkmatter particles. Efficient background reduction is achieved using low radioactivity underground argon as well as several experimental handles such as pulse shape, ratio of ionization over scintillation signal, 3D event reconstruction, and active neutron and muon vetos. The DarkSide-10 prototype detector has proven high scintillation light yield, which is a particularly important parameter as it sets the energy threshold for the pulse shape discrimination technique. The DarkSide-50 detector system, currently in commissioning phase at the Gran Sasso Underground Laboratory, will reach a sensitivity to darkmatter spin-independent scattering cross section of 10-45 cm2 within 3 years of operation.

We treat here the problem of darkmatter in galaxies. Recent articles seem to imply that we are entering into the precision era of cosmology, implying that all of the basic physics of cosmology is known. However, we show here that recent observations question the pillar of the standard model: the presence of nonbaryonic 'darkmatter' in galaxies. Using Newton's law of gravitation, observations indicate that most of the matter in galaxies in invisible or dark. From the observed abundances of light elements, darkmatter in galaxies must be primarily nonbaryonic. The standard model and its problems in explaining nonbaryonic darkmatter will first be discussed. This will be followed by a discussion of a modification of Newton's law of gravitation to explain darkmatter in galaxies. (author)

We have investigated interacting dark energy cosmologies both concerning their impact on the background evolution of the Universe and their effects on cosmological structure growth. For the former aspect, we have developed a cosmological model featuring a matter species consisting of particles with a mass that increases with time. In such model the appearance of a Growing Matter component, which is negligible in early cosmology, dramatically slows down the evolution of the dark energy scalar field at a redshift around six, and triggers the onset of the accelerated expansion of the Universe, therefore addressing the Coincidence Problem. We propose to identify this Growing Matter component with cosmic neutrinos, in which case the present dark energy density can be related to the measured average mass of neutrinos. For the latter aspect, we have implemented the new physical features of interacting dark energy models into the cosmological N-body code GADGET-2, and we present the results of a series of high-resolution simulations for a simple realization of dark energy interaction. As a consequence of the new physics, cold darkmatter and baryon distributions evolve differently both in the linear and in the non-linear regime of structure formation. Already on large scales, a linear bias develops between these two components, which is further enhanced by the non-linear evolution. We also find, in contrast with previous work, that the density profiles of cold darkmatter halos are less concentrated in coupled dark energy cosmologies compared with {lambda}{sub CDM}. Also, the baryon fraction in halos in the coupled models is significantly reduced below the universal baryon fraction. These features alleviate tensions between observations and the {lambda}{sub CDM} model on small scales. Our methodology is ideally suited to explore the predictions of coupled dark energy models in the fully non-linear regime, which can provide powerful constraints for the viable parameter

We have investigated interacting dark energy cosmologies both concerning their impact on the background evolution of the Universe and their effects on cosmological structure growth. For the former aspect, we have developed a cosmological model featuring a matter species consisting of particles with a mass that increases with time. In such model the appearance of a Growing Matter component, which is negligible in early cosmology, dramatically slows down the evolution of the dark energy scalar field at a redshift around six, and triggers the onset of the accelerated expansion of the Universe, therefore addressing the Coincidence Problem. We propose to identify this Growing Matter component with cosmic neutrinos, in which case the present dark energy density can be related to the measured average mass of neutrinos. For the latter aspect, we have implemented the new physical features of interacting dark energy models into the cosmological N-body code GADGET-2, and we present the results of a series of high-resolution simulations for a simple realization of dark energy interaction. As a consequence of the new physics, cold darkmatter and baryon distributions evolve differently both in the linear and in the non-linear regime of structure formation. Already on large scales, a linear bias develops between these two components, which is further enhanced by the non-linear evolution. We also find, in contrast with previous work, that the density profiles of cold darkmatter halos are less concentrated in coupled dark energy cosmologies compared with Λ CDM . Also, the baryon fraction in halos in the coupled models is significantly reduced below the universal baryon fraction. These features alleviate tensions between observations and the Λ CDM model on small scales. Our methodology is ideally suited to explore the predictions of coupled dark energy models in the fully non-linear regime, which can provide powerful constraints for the viable parameter space of such scenarios

A brief description of the status of baryons in the Universe is given, along with recent results from the MACHO collaboration and their meaning. A darkmatter halo consisting of baryons in the form of Machos is ruled out, leaving an elementary particle as the prime candidate for the darkmatter. The observed microlensing events may make up around 20% of the darkmatter in the Milky Way, or may indicate an otherwise undetected component of the Large Magellanic Cloud

We show that quantum gravity, whatever its ultra-violet completion might be, could account for darkmatter. Indeed, besides the massless gravitational field recently observed in the form of gravitational waves, the spectrum of quantum gravity contains two massive fields respectively of spin 2 and spin 0. If these fields are long-lived, they could easily account for darkmatter. In that case, darkmatter would be very light and only gravitationally coupled to the standard model particles.

Darkmatter, first definitely found in the large clusters of galaxies, is now known to be dominant mass in the outer parts of galaxies. All the mass definitely deduced could be made up of baryons, and this would fit well with the requirements of nucleosynthesis in a big bang of small Ω B . However, if inflation is the explanation of the expansion and large scale homogeneity of the universe and of baryon synthesis, and if the universe did not have an infinite extent at the big bang, then Ω should be minutely greater than unity. It is commonly hypothesized that most mass is composed of some unknown, non-baryonic form. This book first discusses the known forms, comets, planets, brown dwarfs, stars, gas, galaxies and Lyman α clouds in which baryons are known to exist. Limits on the amount of darkmatter in baryonic form are discussed in the context of the big bang. Inhomogeneities of the right type alleviate the difficulties associated with Ω B = 1 cosmological nucleosynthesis

Asymmetric darkmatter (ADM) is motivated by the similar cosmological mass densities measured for ordinary and darkmatter. We present a comprehensive theory for ADM that addresses the mass density similarity, going beyond the usual ADM explanations of similar number densities. It features an explicit matter-antimatter asymmetry generation mechanism, has one fully worked out thermal history and suggestions for other possibilities, and meets all phenomenological, cosmological and astrophysical constraints. Importantly, it incorporates a deep reason for why the darkmatter mass scale is related to the proton mass, a key consideration in ADM models. Our starting point is the idea of mirror matter, which offers an explanation for darkmatter by duplicating the standard model with a dark sector related by a Z2 parity symmetry. However, the dark sector need not manifest as a symmetric copy of the standard model in the present day. By utilizing the mechanism of "asymmetric symmetry breaking" with two Higgs doublets in each sector, we develop a model of ADM where the mirror symmetry is spontaneously broken, leading to an electroweak scale in the dark sector that is significantly larger than that of the visible sector. The weak sensitivity of the ordinary and dark QCD confinement scales to their respective electroweak scales leads to the necessary connection between the darkmatter and proton masses. The darkmatter is composed of either dark neutrons or a mixture of dark neutrons and metastable dark hydrogen atoms. Lepton asymmetries are generated by the C P -violating decays of heavy Majorana neutrinos in both sectors. These are then converted by sphaleron processes to produce the observed ratio of visible to darkmatter in the universe. The dynamics responsible for the kinetic decoupling of the two sectors emerges as an important issue that we only partially solve.

Darkmatter detection experiments are improving to the point where they can detect or restrict the primary particle physics candidates for non baryonic darkmatter. The methods for detection are usually categorized as direct, i.e., searching for signals caused by passage of darkmatter particles in terrestrial detectors, or indirect. Indirect detection methods include searching for antimatter and gamma rays, in particular gamma ray lines, in cosmic rays and high-energy neutrinos from the centre of the Earth or Sun caused by accretion and annihilation of darkmatter particles. A review is given of recent progress in indirect detection, both on the theoretical and experimental side

This proceedings contribution reports from the workshop DarkMatter - a light move, held at DESY in Hamburg in June 2013. DarkMatter particle candidates span a huge parameter range. In particular, well motivated candidates exist also in the sub-eV mass region, for example the axion. Whilst a plethora of searches for rather heavy DarkMatter particles exists, there are only very few experiments aimed at direct detection of sub-eV DarkMatter to this date. The aim of our workshop was to discuss if and how this could be changed in the near future.

This proceedings contribution reports from the workshop DarkMatter - a light move, held at DESY in Hamburg in June 2013. DarkMatter particle candidates span a huge parameter range. In particular, well motivated candidates exist also in the sub-eV mass region, for example the axion. Whilst a plethora of searches for rather heavy DarkMatter particles exists, there are only very few experiments aimed at direct detection of sub-eV DarkMatter to this date. The aim of our workshop was to discuss if and how this could be changed in the near future.

We now believe that the darkmatter in our Universe must be an unknown elementary particle, which is charge neutral and weakly interacting. The standard model must be extended to include it. The darkmatter was likely produced in the early universe from the high energy collisions of the particles. Now LHC experiment starting from 2008 will create such high energy collision to explore the nature of the darkmatter. In this article we explain how darkmatter and LHC physics will be connected in detail. (author)

The existence of cosmological darkmatter is in the bedrock of the modern cosmology. The darkmatter is assumed to be nonbaryonic and consists of new stable particles. Weakly Interacting Massive Particle (WIMP) miracle appeals to search for neutral stable weakly interacting particles in underground experiments by their nuclear recoil and at colliders by missing energy and momentum, which they carry out. However, the lack of WIMP effects in their direct underground searches and at colliders can appeal to other forms of darkmatter candidates. These candidates may be weakly interacting slim particles, superweakly interacting particles, or composite darkmatter, in which new particles are bound. Their existence should lead to cosmological effects that can find probes in the astrophysical data. However, if composite darkmatter contains stable electrically charged leptons and quarks bound by ordinary Coulomb interaction in elusive dark atoms, these charged constituents of dark atoms can be the subject of direct experimental test at the colliders. The models, predicting stable particles with charge ‑ 2 without stable particles with charges + 1 and ‑ 1 can avoid severe constraints on anomalous isotopes of light elements and provide solution for the puzzles of darkmatter searches. In such models, the excessive ‑ 2 charged particles are bound with primordial helium in O-helium atoms, maintaining specific nuclear-interacting form of the darkmatter. The successful development of composite darkmatter scenarios appeals for experimental search for doubly charged constituents of dark atoms, making experimental search for exotic stable double charged particles experimentum crucis for dark atoms of composite darkmatter.

For nearly a century, more mass has been measured in galaxies than is contained in the luminous stars and gas. Through continual advances in observations and theory, it has become clear that the darkmatter in galaxies is not comprised of known astronomical objects or baryonic matter, and that identification of it is certain to reveal a profound connection between astrophysics, cosmology, and fundamental physics. The best explanation for darkmatter is that it is in the form of a yet undiscovered particle of nature, with experiments now gaining sensitivity to the most well-motivated particle darkmatter candidates. In this article, I review measurements of darkmatter in the Milky Way and its satellite galaxies and the status of Galactic searches for particle darkmatter using a combination of terrestrial and space-based astroparticle detectors, and large scale astronomical surveys. I review the limits on the darkmatter annihilation and scattering cross sections that can be extracted from both astroparticle experiments and astronomical observations, and explore the theoretical implications of these limits. I discuss methods to measure the properties of particle darkmatter using future experiments, and conclude by highlighting the exciting potential for darkmatter searches during the next decade, and beyond

It is usually thought that the present mass density of the Universe is dominated by a weakly interacting massive particle (WIMP), a fossil relic of the early Universe. Theoretical ideas and experimental efforts have focused mostly on production and detection of thermal relics, with mass typically in the range a few GeV to a hundred GeV. Here, we will review scenarios for production of nonthermal darkmatter whose mass may be in the range 10/sup 12/ to 10/sup 19/ GeV, much larger than the mass of thermal wimpy WIMPS. We will also review recent related results in understanding the production of very heavy fermions through preheating after inflation. (19 refs).

We review the physics case for very weakly coupled ultralight particles beyond the Standard Model, in particular for axions and axion-like particles (ALPs): (i) the axionic solution of the strong CP problem and its embedding in well motivated extensions of the Standard Model; (ii) the possibility that the cold darkmatter in the Universe is comprised of axions and ALPs; (iii) the ALP explanation of the anomalous transparency of the Universe for TeV photons; and (iv) the axion or ALP explanation of the anomalous energy loss of white dwarfs. Moreover, we present an overview of ongoing and near-future laboratory experiments searching for axions and ALPs: haloscopes, helioscopes, and light-shining-through-a-wall experiments.

We review the physics case for very weakly coupled ultralight particles beyond the Standard Model, in particular for axions and axion-like particles (ALPs): (i) the axionic solution of the strong CP problem and its embedding in well motivated extensions of the Standard Model; (ii) the possibility that the cold darkmatter in the Universe is comprised of axions and ALPs; (iii) the ALP explanation of the anomalous transparency of the Universe for TeV photons; and (iv) the axion or ALP explanation of the anomalous energy loss of white dwarfs. Moreover, we present an overview of ongoing and near-future laboratory experiments searching for axions and ALPs: haloscopes, helioscopes, and light-shining-through-a-wall experiments.

scale of the solar system. Galaxy, Darkmatter , Galaxy cluster, Gravitation, Quantum gravity...A two parameter exponential potential explains the anomalous kinematics of galaxies and galaxy clusters without need for the myriad ad hoc dark ... matter models currently in vogue. It also explains much about the scales and structures of galaxies and galaxy clusters while being quite negligible on the

The current status of indirect searches for darkmatter has been reviewed in a schematic way here. The main relevant experimental results of the recent years have been listed and the excitements and disappointments that their phenomenological interpretations in terms of almost-standard annihilating darkmatter have ...

Darkmatter with strong self-interactions provides a compelling solution to several small-scale structure puzzles. Under the assumption that the coupling between darkmatter and the Standard Model particles is suppressed, such strongly interacting massive particles (SIMPs) allow for a successful thermal freeze-out through N-to-N' processes, where N darkmatter particles annihilate to N' of them. In the most common scenarios, where darkmatter stability is guaranteed by a Z 2 symmetry, the seemingly leading annihilating channel, i.e. 3-to-2 process, is forbidden, so the 4-to-2 one dominate the production of the darkmatter relic density. Moreover, cosmological observations require that the darkmatter sector is colder than the thermal bath of Standard Model particles, a condition that can be dynamically generated via a small portal between darkmatter and Standard Model particles, à la freeze-in. This scenario is exemplified in the context of the Singlet Scalar darkmatter model

Darkmatter constitutes a key-problem at the interface between Particle Physics, Astrophysics and Cosmology. Indeed, the observational facts which have been accumulated in the last years on darkmatter point to the existence of an amount of non-baryonic darkmatter. Since the Standard Model of Particle Physics does not possess any candidate for such non-baryonic darkmatter, this problem constitutes a major indication for new Physics beyond the Standard Model. We analyze the most important candidates for non-baryonic darkmatter in the context of extensions of the Standard Model (in particular supersymmetric models). The recent hints for the presence of a large amount of unclustered 'vacuum' energy (cosmological constant?) is discussed from the Astrophysical and Particle Physics perspective. (author)

The darkmatter problem is one of the most fundamental and profoundly difficult to solve problems in the history of science. Not knowing what makes up most of the known universe goes to the heart of our understanding of the Universe and our place in it. In Search of DarkMatter is the story of the emergence of the darkmatter problem, from the initial erroneous ‘discovery’ of darkmatter by Jan Oort to contemporary explanations for the nature of darkmatter and its role in the origin and evolution of the Universe. Written for the educated non-scientist and scientist alike, it spans a variety of scientific disciplines, from observational astronomy to particle physics. Concepts that the reader will encounter along the way are at the cutting edge of scientific research. However the themes are explained in such a way that no prior understanding of science beyond a high school education is necessary.

The cosmological mean matter (dark and baryonic) density measured in the units of the critical density is Ωm = 0.27. Independently, the local mean density is estimated to be Ωloc = 0.08-0.23 from recent data on galaxy groups at redshifts up to z = 0.01-0.03 (as published by Crook et al. 2007, ApJ, 655, 790 and Makarov & Karachentsev 2011, MNRAS, 412, 2498). If the lower values of Ωloc are reliable, as Makarov & Karachentsev and some other observers prefer, does this mean that the Local Universe of 100-300 Mpc across is an underdensity in the cosmic matter distribution? Or could it nevertheless be representative of the mean cosmic density or even be an overdensity due to the Local Supercluster therein. We focus on darkmatter halos of groups of galaxies and check how much dark mass the invisible outer layers of the halos are able to host. The outer layers are usually devoid of bright galaxies and cannot be seen at large distances. The key factor which bounds the size of an isolated halo is the local antigravity produced by the omnipresent background of dark energy. A gravitationally bound halo does not extend beyond the zero-gravity surface where the gravity of matter and the antigravity of dark energy balance, thus defining a natural upper size of a system. We use our theory of local dynamical effects of dark energy to estimate the maximal sizes and masses of the extended dark halos. Using data from three recent catalogs of galaxy groups, we show that the calculated mass bounds conform with the assumption that a significant amount of darkmatter is located in the invisible outer parts of the extended halos, sufficient to fill the gap between the observed and expected local matter density. Nearby groups of galaxies and the Virgo cluster have dark halos which seem to extend up to their zero-gravity surfaces. If the extended halo is a common feature of gravitationally bound systems on scales of galaxy groups and clusters, the Local Universe could be typical or even

Astrophysicists now know that 80% of the matter in the universe is 'darkmatter', composed of neutral and weakly interacting elementary particles that are not part of the Standard Model of particle physics. I will summarize the evidence for darkmatter. I will explain why I expect darkmatter particles to be produced at the CERN LHC. We will then need to characterize the new weakly interacting particles and demonstrate that they the same particles that are found in the cosmos. I will describe how this might be done. (author)

Asymmetric DarkMatter (ADM) models invoke a particle-antiparticle asymmetry, similar to the one observed in the Baryon sector, to account for the DarkMatter (DM) abundance. Both asymmetries are usually generated by the same mechanism and generally related, thus predicting DM masses around 5 GeV in order to obtain the correct density. The main challenge for successful models is to ensure efficient annihilation of the thermally produced symmetric component of such a light DM candidate without violating constraints from collider or direct searches. A common way to overcome this involves a light mediator, into which DM can efficiently annihilate and which subsequently decays into Standard Model particles. Here we explore the scenario where the light mediator decays instead into lighter degrees of freedom in the dark sector that act as radiation in the early Universe. While this assumption makes indirect DM searches challenging, it leads to signals of extra radiation at BBN and CMB. Under certain conditions, precise measurements of the number of relativistic species, such as those expected from the Planck satellite, can provide information on the structure of the dark sector. We also discuss the constraints of the interactions between DM and Dark Radiation from their imprint in the matter power spectrum

A brief overview is given of the phenomenology of particle darkmatter and the properties of some of the most widely studied darkmatter candidates. Recent developments in direct and indirect darkmatter searches are discussed.

Asymmetric DarkMatter (ADM) models invoke a particle-antiparticle asymmetry, similar to the one observed in the Baryon sector, to account for the DarkMatter (DM) abundance. Both asymmetries are usually generated by the same mechanism and generally related, thus predicting DM masses around 5 GeV in order to obtain the correct density. The main challenge for successful models is to ensure efficient annihilation of the thermally produced symmetric component of such a light DM candidate without violating constraints from collider or direct searches. A common way to overcome this involves a light mediator, into which DM can efficiently annihilate and which subsequently decays into Standard Model particles. Here we explore the scenario where the light mediator decays instead into lighter degrees of freedom in the dark sector that act as radiation in the early Universe. While this assumption makes indirect DM searches challenging, it leads to signals of extra radiation at BBN and CMB. Under certain conditions, pre...

A nonlocal generalization of Einstein's theory of gravitation is constructed within the framework of the translational gauge theory of gravity. In the linear approximation, the nonlocal theory can be interpreted as linearized general relativity but in the presence of "darkmatter" that can be simply expressed as an integral transform of matter. It is shown that this approach can accommodate the Tohline-Kuhn treatment of the astrophysical evidence for darkmatter.

Asymmetric darkmatter (ADM) is motivated by the similar cosmological mass densities measured for ordinary and darkmatter. We present a comprehensive theory for ADM that addresses the mass density similarity, going beyond the usual ADM explanations of similar number densities. It features an explicit matter-antimatter asymmetry generation mechanism, has one fully worked out thermal history and suggestions for other possibilities, and meets all phenomenological, cosmological and astrophysical...

Sterile neutrinos produced through oscillations are a well motivated darkmatter candidate, but recent constraints from observations have ruled out most of the parameter space. We analyze the impact of new interactions on the evolution of keV sterile neutrino darkmatter in the early Universe. Based on general considerations we find a mechanism which thermalizes the sterile neutrinos after an initial production by oscillations. The thermalization of sterile neutrinos is accompanied by dark entropy production which increases the yield of darkmatter and leads to a lower characteristic momentum. This resolves the growing tensions with structure formation and x-ray observations and even revives simple nonresonant production as a viable way to produce sterile neutrino darkmatter. We investigate the parameters required for the realization of the thermalization mechanism in a representative model and find that a simple estimate based on energy and entropy conservation describes the mechanism well.

Sterile neutrinos produced through oscillations are a well motivated darkmatter candidate, but recent constraints from observations have ruled out most of the parameter space. We analyze the impact of new interactions on the evolution of keV sterile neutrino darkmatter in the early Universe. Based on general considerations we find a mechanism which thermalizes the sterile neutrinos after an initial production by oscillations. The thermalization of sterile neutrinos is accompanied by dark entropy production which increases the yield of darkmatter and leads to a lower characteristic momentum. This resolves the growing tensions with structure formation and x-ray observations and even revives simple nonresonant production as a viable way to produce sterile neutrino darkmatter. We investigate the parameters required for the realization of the thermalization mechanism in a representative model and find that a simple estimate based on energy and entropy conservation describes the mechanism well.

We revisit constraints on darkmatter that is charged under a U(1) gauge group in the dark sector, decoupled from Standard Model forces. We find that the strongest constraints in the literature are subject to a number of mitigating factors. For instance, the naive darkmatter thermalization timescale in halos is corrected by saturation effects that slow down isotropization for modest ellipticities. The weakened bounds uncover interesting parameter space, making models with weak-scale charged darkmatter viable, even with electromagnetic strength interaction. This also leads to the intriguing possibility that darkmatter self-interactions within small dwarf galaxies are extremely large, a relatively unexplored regime in current simulations. Such strong interactions suppress heat transfer over scales larger than the darkmatter mean free path, inducing a dynamical cutoff length scale above which the system appears to have only feeble interactions. These effects must be taken into account to assess the viability of darkly-charged darkmatter. Future analyses and measurements should probe a promising region of parameter space for this model.

Darkmatter in spiral galaxies like the Milky Way may take the form of a dark plasma. Hidden sector darkmatter charged under an unbroken U(1)' gauge interaction provides a simple and well defined particle physics model realising this possibility. The assumed U(1)' neutrality of the Universe then implies (at least) two oppositely charged darkmatter components with self-interactions mediated via a massless 'dark photon' (the U(1)' gauge boson). In addition to nuclear recoils such darkmatter can give rise to keV electron recoils in direct detection experiments. In this context, the detailed physical properties of the darkmatter plasma interacting with the Earth is required. This is a complex system, which is here modelled as a fluid governed by the magnetohydrodynamic equations. These equations are numerically solved for some illustrative examples, and implications for direct detection experiments discussed. In particular, the analysis presented here leaves open the intriguing possibility that the DAMA annual modulation signal is due primarily to electron recoils (or even a combination of electron recoils and nuclear recoils). The importance of diurnal modulation (in addition to annual modulation) as a means of probing this kind of darkmatter is also emphasised.

In this work we perform a comprehensive statistical analysis of the AMS-02 electron, positron fluxes and the antiproton-to-proton ratio in the context of a simplified darkmatter model. We include known, standard astrophysical sources and a darkmatter component in the cosmic ray injection spectra. To predict the AMS-02 observables we use propagation parameters extracted from observed fluxes of heavier nuclei and the low energy part of the AMS-02 data. We assume that the darkmatter particle is a Majorana fermion coupling to third generation fermions via a spin-0 mediator, and annihilating to multiple channels at once. The simultaneous presence of various annihilation channels provides the darkmatter model with additional flexibility, and this enables us to simultaneously fit all cosmic ray spectra using a simple particle physics model and coherent astrophysical assumptions. Our results indicate that AMS-02 observations are not only consistent with the darkmatter hypothesis within the uncertainties, but adding a darkmatter contribution improves the fit to the data. Assuming, however, that darkmatter is solely responsible for this improvement of the fit, it is difficult to evade the latest CMB limits in this model.

A hidden sector with a mass gap undergoes an epoch of cannibalism if number changing interactions are active when the temperature drops below the mass of the lightest hidden particle. During cannibalism, the hidden sector temperature decreases only logarithmically with the scale factor. We consider the possibility that darkmatter resides in a hidden sector that underwent cannibalism, and has relic density set by the freeze-out of two-to-two annihilations. We identify three novel phases, depending on the behavior of the hidden sector when darkmatter freezes out. During the cannibal phase, darkmatter annihilations decouple while the hidden sector is cannibalizing. During the chemical phase, only two-to-two interactions are active and the total number of hidden particles is conserved. During the one way phase, the darkmatter annihilation products decay out of equilibrium, suppressing the production of darkmatter from inverse annihilations. We map out the distinct phenomenology of each phase, which includes a boosted darkmatter annihilation rate, new relativistic degrees of freedom, warm darkmatter, and observable distortions to the spectrum of the cosmic microwave background.

In this work we perform a comprehensive statistical analysis of the AMS-02 electron, positron fluxes and the antiproton-to-proton ratio in the context of a simplified darkmatter model. We include known, standard astrophysical sources and a darkmatter component in the cosmic ray injection spectra. To predict the AMS-02 observables we use propagation parameters extracted from observed fluxes of heavier nuclei and the low energy part of the AMS-02 data. We assume that the darkmatter particle is a Majorana fermion coupling to third generation fermions via a spin-0 mediator, and annihilating to multiple channels at once. The simultaneous presence of various annihilation channels provides the darkmatter model with additional flexibility, and this enables us to simultaneously fit all cosmic ray spectra using a simple particle physics model and coherent astrophysical assumptions. Our results indicate that AMS-02 observations are not only consistent with the darkmatter hypothesis within the uncertainties, but adding a darkmatter contribution improves the fit to the data. Assuming, however, that darkmatter is solely responsible for this improvement of the fit, it is difficult to evade the latest CMB limits in this model.

If darkmatter (DM) has nonzero direct or transition, electric or magnetic dipole moment then it can scatter nucleons electromagnetically in direct detection experiments. Using the results from experiments like XENON, CDMS, DAMA, and COGENT, we put bounds on the electric and magnetic dipole moments of DM. If DM consists of Dirac fermions with direct dipole moments, then DM of mass less than 10 GeV is consistent with the DAMA signal and with null results of other experiments. If on the other hand DM consists of Majorana fermions then they can have only nonzero transition moments between different mass eigenstates. We find that Majorana fermions with masses 38 χ < or approx. 100-200 GeV and mass splitting of the order of (150-200) keV can explain the DAMA signal and the null observations from other experiments and in addition give the observed relic density of DM by dipole-mediated annihilation. The absence of the heavier DM state in the present Universe can be explained by dipole-mediated radiative decay. This parameter space for the mass and for dipole moments is allowed by limits from L3 but may have observable signals at LHC.

The axion is arguably one of the best motivated candidates for darkmatter. For a decay constant >or similar 10 9 GeV, axions are dominantly produced non-thermally in the early universe and hence are ''cold'', their velocity dispersion being small enough to fit to large scale structure. Moreover, such a large decay constant ensures the stability at cosmological time scales and its behaviour as a collisionless fluid at cosmological length scales. Here, we review the state of the art of axion darkmatter predictions and of experimental efforts to search for axion darkmatter in laboratory experiments.

The axion is arguably one of the best motivated candidates for darkmatter. For a decay constant >or similar 10{sup 9} GeV, axions are dominantly produced non-thermally in the early universe and hence are ''cold'', their velocity dispersion being small enough to fit to large scale structure. Moreover, such a large decay constant ensures the stability at cosmological time scales and its behaviour as a collisionless fluid at cosmological length scales. Here, we review the state of the art of axion darkmatter predictions and of experimental efforts to search for axion darkmatter in laboratory experiments.

The presence of a non-baryonic darkmatter component in the Universe is inferred from the observation of its gravitational interaction. If darkmatter interacts weakly with the Standard Model it would be produced at the LHC, escaping the detector and leaving a large missing transverse momentum as their signature. The ATLAS detector has developed a broad and systematic search program for darkmatter production in LHC collisions. The results of these searches on the first 13 TeV data, their interpretation, and the design and possible evolution of the search program will be presented.

This article is an experimental review of the status and prospects of indirect searches for darkmatter. Experiments observe secondary particles such as positrons, antiprotons, antideuterons, gamma-rays and neutrinos which could originate from annihilations of darkmatter particles in various locations in the galaxy. Data exist from some experiments which have been interpreted as hints of evidence for darkmatter. These data and their interpretations are reviewed together with the new experiments which are planned to resolve the puzzles and make new measurements which could give unambiguous results

The simplest model that can accommodate a viable nonbaryonic darkmatter candidate is the standard electroweak theory with the addition of right-handed (sterile) neutrinos. We consider a single generation of neutrinos with a Dirac mass μ and a Majorana mass M for the right-handed component. If M much-gt μ (standard hot darkmatter corresponds to M=0), then sterile neutrinos are produced via oscillations in the early Universe with energy density independent of M. However, M is crucial in determining the large scale structure of the Universe; for M∼100 eV, sterile neutrinos make an excellent warm darkmatter candidate

The prospects for detecting a candidate supersymmetric darkmatter particle at the LHC are reviewed, and compared with the prospects for direct and indirect searches for astrophysical darkmatter. The discussion is based on a frequentist analysis of the preferred regions of the Minimal supersymmetric extension of the Standard Model with universal soft supersymmetry breaking (the CMSSM). LHC searches may have good chances to observe supersymmetry in the near future - and so may direct searches for astrophysical darkmatter particles, whereas indirect searches may require greater sensitivity, at least within the CMSSM.

The main candidates to darkmatter are particles called WIMPs for weakly interacting massive particles. 4 experiments (CDMS in Minnesota (Usa), DAMA at Gran Sasso (Italy), CoGeNT in Minnesota (Usa) and PAMELA onboard a Russian satellite) have claimed to have detected them. New clues suggest that it could exist new particles interacting via new forces. The observation that dwarf galaxies are systematically more spherical than massive galaxies might be a sign of the existence of new forces between darkmatter components. Darkmatter could not be as inert as previously thought. (A.C.)

Most matter in the universe consists of 'darkmatter' unknown to particle physics. Deep underground detectors such as XENON1T attempt to detect rare collisions of darkmatter with ordinary atoms. This thesis describes the first darkmatter search of XENON1T, how darkmatter signals would appear in

Dark energy in the universe is assumed to be vacuum energy. The energy-momentum of vacuum is described by a scale-dependent cosmological constant. The equations of motion imply for the density of matter (dust) the sum of the usual matter density (luminous matter) and an additional matter density (darkmatter) similar to the dark energy. The scale-dependent cosmological constant is given up to an exponent which is approximated by the experimentally decided density parameters of darkmatter and...

As only 0.5 per cent (the shining part) of the Universe is seen by telescopes, and corresponds to a tenth of ordinary matter or 5 per cent of the cosmos, astrophysicists postulated that the remaining 95 per cent are made of darkmatter and dark energy. But always more researchers put the existence of this darkmatter and energy into question again. They notably think of giving up Newton's law of universal gravitation, and also the basic assumption of cosmology, i.e. the homogeneous character of the Universe. The article recalls the emergence of the notion of darkmatter to explain the fact that stars stay within a galaxy, whereas with their observed speed and the application of the gravitational theory they should escape their galaxy. Then, the issue has been to find evidence of the existence of darkmatter. Neutrinos were supposed to be a clue, but only for a while. The notion of dark energy was introduced more recently by researchers who, by the observation of supernovae, noticed that the Universe expansion was accelerated in time. Then, after having discussed the issues raised by the possible existence of dark energy, the article explains how and why a new non homogeneous cosmology emerged. It also evokes current and future researches in this field. In an interview, an astrophysicist outlines why we should dare to modify Newton's law

Although darkmatter is a central element of modern cosmology, the history of how it became accepted as part of the dominant paradigm is often ignored or condensed into a brief anecdotical account focused around the work of a few pioneering scientists. The aim of this review is to provide the reader with a broader historical perspective on the observational discoveries and the theoretical arguments that led the scientific community to adopt darkmatter as an essential part of the standard cosmological model.

Full Text Available General considerations in general relativity and quantum mechanics are known to potentially rule out continuous global symmetries in the context of any consistent theory of quantum gravity. Assuming the validity of such considerations, we derive stringent bounds from gamma-ray, X-ray, cosmic-ray, neutrino, and CMB data on models that invoke global symmetries to stabilize the darkmatter particle. We compute up-to-date, robust model-independent limits on the darkmatter lifetime for a variety of Planck-scale suppressed dimension-five effective operators. We then specialize our analysis and apply our bounds to specific models including the Two-Higgs-Doublet, Left–Right, Singlet Fermionic, Zee–Babu, 3-3-1 and Radiative See-Saw models. Assuming that (i global symmetries are broken at the Planck scale, that (ii the non-renormalizable operators mediating darkmatter decay have O(1 couplings, that (iii the darkmatter is a singlet field, and that (iv the darkmatter density distribution is well described by a NFW profile, we are able to rule out fermionic, vector, and scalar darkmatter candidates across a broad mass range (keV–TeV, including the WIMP regime.

We present Self-Destructing DarkMatter (SDDM), a new class of darkmatter models which are detectable in large neutrino detectors. In this class of models, a component of darkmatter can transition from a long-lived state to a short-lived one by scattering off of a nucleus or an electron in the Earth. The short-lived state then decays to Standard Model particles, generating a darkmatter signal with a visible energy of order the darkmatter mass rather than just its recoil. This leads to striking signals in large detectors with high energy thresholds. We present a few examples of models which exhibit self destruction, all inspired by bound state dynamics in the Standard Model. The models under consideration exhibit a rich phenomenology, possibly featuring events with one, two, or even three lepton pairs, each with a fixed invariant mass and a fixed energy, as well as non-trivial directional distributions. This motivates dedicated searches for darkmatter in large underground detectors such as Super-K, Borexino, SNO+, and DUNE.

Darkmatter pervades the universe. While it is invisible to us, we can detect its influence on matter we can see. To illuminate this concept, we have created an interactive javascript program illustrating predictions made by six different models for darkmatter distributions in galaxies. Students are able to match the predicted data with actual experimental results, drawn from several astronomy papers discussing dark matter’s impact on galactic rotation curves. Programming each new model requires integration of density equations with parameters determined by nonlinear curve-fitting using MATLAB scripts we developed. Using our javascript simulation, students can determine the most plausible darkmatter models as well as the average percentage of darkmatter lurking in galaxies, areas where the scientific community is still continuing to research. In that light, we strive to use the most up-to-date and accepted concepts: two of our darkmatter models are the pseudo-isothermal halo and Navarro-Frenk-White, and we integrate out to each galaxy’s virial radius. Currently, our simulation includes NGC3198, NGC2403, and our own Milky Way.

Modified darkmatter (MDM) is a phenomenological model of darkmatter, inspired by gravitational thermodynamics. For an accelerating universe with positive cosmological constant (Λ), such phenomenological considerations lead to the emergence of a critical acceleration parameter related to Λ. Such a critical acceleration is an effective phenomenological manifestation of MDM, and it is found in correlations between darkmatter and baryonic matter in galaxy rotation curves. The resulting MDM mass profiles, which are sensitive to Λ, are consistent with observational data at both the galactic and cluster scales. In particular, the same critical acceleration appears both in the galactic and cluster data fits based on MDM. Furthermore, using some robust qualitative arguments, MDM appears to work well on cosmological scales, even though quantitative studies are still lacking. Finally, we comment on certain nonlocal aspects of the quanta of modified darkmatter, which may lead to novel nonparticle phenomenology and which may explain why, so far, darkmatter detection experiments have failed to detect darkmatter particles.

Experiments housed deep underground are searching for new particles that could simultaneously solve one of the biggest mysteries in astrophysics and reveal what lies beyond the Standard Model of particle physics. Physicists are very particular about balancing budgets. Energy, charge and momentum all have to be conserved and often money as well. Astronomers were therefore surprised and disturbed to learn in the 1930s that our own Milky Way galaxy behaved as if it contained more matter than could be seen with telescopes. This puzzling non-luminous matter became known as ''darkmatter'' and we now know that over 90% of the matter in the entire universe is dark. In later decades the search for this darkmatter shifted from the heavens to the Earth. In fact, the search for darkmatter went underground. Today there are experiments searching for darkmatter hundreds and thousands of metres below ground in mines, road tunnels and other subterranean locations. These experiments are becoming more sensitive every year and are beginning to test various new models and theories in particle physics and cosmology. (UK)

We consider the prospects for multiple darkmatter direct detection experiments to determine if the interactions of a darkmatter candidate are isospin-violating. We focus on theoretically well-motivated examples of isospin-violating darkmatter (IVDM), including models in which darkmatter interactions with nuclei are mediated by a dark photon, a Z, or a squark. We determine that the best prospects for distinguishing IVDM from the isospin-invariant scenario arise in the cases of dark photon–...

The number of baryons (protons and neutrons) of the universe can be deduced from the relative abundances of light elements (deuterium, helium and lithium) that were generated during the very first minutes of the cosmic history. This calculation has shown that the baryonic matter represents only 5% of the total mass of the universe. As for neutrinos (hot darkmatter), their very low mass restraints their contribution to only 0,3%. The spinning movement of galaxies requires the existence of huge quantity of matter that seems invisible (black matter). Astrophysicists have recently discovered that the universal expansion is accelerating and that the space geometry is euclidean, from these 2 facts they have deduced a value of the mass-energy density that implies the existence of something different from darkmatter called dark energy and that is expected to represent about 70% of the mass of the universe. Physicists face the challenge of detecting black matter and black energy. The first attempt for detecting black matter began in 1997 when the UKDMC detector entered into service. Now more than half a dozen of detectors are searching for darkmatter but till now in vain. A new generation of detectors (CDMS-2, ZEPLIN-2, CRESST-2 and Edelweiss-2) combining detection, new methods of particle discrimination and the study of the evolution of the signal over very long periods of time are progressively entering into operation. (A.C.)

In the purely gravitational darkmatter scenario, the darkmatter particle does not have any interaction except for gravitational one. We study the gravitational particle production of darkmatter particle in such a minimal setup and show that correct amount of darkmatter can be produced depending on the inflation model and the darkmatter mass. In particular, we carefully evaluate the particle production rate from the transition epoch to the inflaton oscillation epoch in a realistic inflati...

We consider the cross section limits for light darkmatter cadnidates (m=0.4 to 10 GeV). We calculate the interaction of darkmatter in the crust above underground darkmatter detectors and find that in the intermediate cross section range, the energy loss of darkmatter is sufficient to fall below the energy threshold of current underground experiments. This implies the existence of a window in the darkmatter exclusion limits in the micro-barn range

The standard model of cosmology suggests the existence of two components, "darkmatter" and "dark energy", which determine the fate of the Universe. Their nature is still under investigation, and no direct proof of their existences has emerged yet. There exist alternative models which reinterpret the cosmological observations, for example by replacing the dark energy/darkmatter hypothesis by the existence of a unique dark component, the dark fluid, which is able to mimic the behaviour of bot...

We consider the conditions needed to unify the description of darkmatter, dark energy and inflation in the context of the string landscape. We find that incomplete decay of the inflaton field gives the possibility that a single field is responsible for all three phenomena. By contrast, unifying darkmatter and dark energy into a single field, separate from the inflaton, appears rather difficult.

We show that darkmatter abundance and the inflationary scale H could be intimately related. Standard Model extensions with Higgs mediated couplings to new physics typically contain extra scalars displaced from vacuum during inflation. If their coupling to Standard Model is weak, they will not thermalize and may easily constitute too much darkmatter reminiscent to the moduli problem. As an example we consider Standard Model extended by a Z{sub 2} symmetric singlet s coupled to the Standard Model Higgs Φ via λ Φ{sup †}Φ s{sup 2}. Darkmatter relic density is generated non-thermally for λ ∼dark matter yield crucially depends on the inflationary scale. For H∼ 10{sup 10} GeV we find that the singlet self-coupling and mass should lie in the regime λ{sub s}∼> 10{sup −9} and m{sub s}∼dark matter overproduction.

To theoretically describe the measured rotational velocity curves of spiral galaxies, there are two different approaches and conclusions. (1) ORDINARY DARKMATTER. We assume Newtonian gravity/dynamics and successfully find (via computer) mass distributions in bulge/disk configurations that duplicate the measured rotational velocities. There is ordinary darkmatter within the galactic disk towards the cooler periphery which has lower emissivity/opacity. There are no mysteries in this scenario based on verified physics. (2) MYSTERIOUS DARKMATTER. Others INaccurately assume the galactic mass distributions follow the measured light distributions, and then the measured rotational velocity curves are NOT duplicated. To alleviate this discrepancy, speculations are invoked re ``Massive Peripheral Spherical Halos of Mysterious DarkMatter.'' But NO matter has been detected in this UNtenable Halo configuration. Many UNverified ``Mysteries'' are invoked as necessary and convenient. CONCLUSION. The first approach utilizing Newtonian gravity/dynamics and searching for the ordinary mass distributions within the galactic disk simulates reality and agrees with data.

Mass models of spiral galaxies based on the observed light distribution, assuming constant M/L for bulge and disc, are able to reproduce the observed rotation curves in the inner regions, but fail to do so increasingly towards and beyond the edge of the visible material. The discrepancy in the outer region can be accounted for by invoking darkmatter; some galaxies require at least four times as much darkmatter as luminous matter. There is no evidence for a dependence on galaxy luminosity or morphological type. Various arguments support the idea that a distribution of visible matter with constant M/L is responsible for the circular velocity in the inner region, i.e. inside approximately 2.5 disc scalelengths. Luminous matter and darkmatter seem to 'conspire' to produce the flat observed rotation curves in the outer region. It seems unlikely that this coupling between disc and halo results from the large-scale gravitational interaction between the two components. Attempts to determine the shape of dark halos have not yet produced convincing results. (author)

Empirical and theoretical evidence show that the astrophysical problem of darkmatter might be solved by a theory of Einstein-Mayer type. In this theory up to global Lorentz rotations the reference system is determined by the motion of cosmic matter. Thus one is led to a "Riemannian space with teleparallelism" realizing a geometric version of the Mach-Einstein doctrine. The field equations of this gravitational theory contain hidden matter terms where the existence of hidden matter is inferred safely from its gravitational effects. It is argued that in the nonrelativistic mechanical approximation they provide an inertia-free mechanics where the inertial mass of a body is induced by the gravitational action of the comic masses. Interpreted form the Newtonian point of view this mechanics shows that the effective gravitational mass of astrophysical objects depends on r such that one expects the existence of darkmatter.

Our Universe is comprised not only of normal matter but also of unknown components: darkmatter and dark energy. This Thesis recounts studies of darkmatter haloes, using a technique known as weak gravitational lensing, in order to learn more about the nature of these dark components. The haloes

If DarkMatter interacts weakly with the Standard Model it can be produced at the LHC. It can be identified via initial state radiation (ISR) of the incoming partons, leaving a signature in the detector of the ISR particle (jet, photon, Z or W) recoiling off of the invisible DarkMatter particles, resulting in a large momentum imbalance. Many signatures of large missing transverse momentum recoiling against jets, photons, heavy-flavor quarks, weak gauge bosons or Higgs bosons provide an interesting channel for DarkMatter searches. These LHC searches complement those from (in)direct detection experiments. Results of these searches with the ATLAS experiment, in both effective field theory and simplified models with pair WIMP production are discussed. Both 8TeV and 13TeV pp collision data has been used in these results.

The study of darkmatter, in both astrophysics and particle physics, has emerged as one of the most active and exciting topics of research in recent years. This book reviews the history behind the discovery of missing mass (or unseen mass) in the universe, and ties this into the proposed extensions to the Standard Model of Particle Physics (such as Supersymmetry), which were being proposed within the same time frame. This book is written as an introduction to these problems at the forefront of astrophysics and particle physics, with the goal of conveying the physics of darkmatter to beginning undergraduate majors in scientific fields. The book goes on to describe existing and upcoming experiments and techniques, which will be used to detect darkmatter either directly or indirectly.

We explore the phenomenology of Elastically Decoupling Relic (ELDER) darkmatter. ELDER is a thermal relic whose present density is determined primarily by the cross-section of its elastic scattering off Standard Model (SM) particles. Assuming that this scattering is mediated by a kinetically mixed dark photon, we argue that the ELDER scenario makes robust predictions for electron-recoil direct-detection experiments, as well as for dark photon searches. These predictions are independent of the details of interactions within the dark sector. Together with the closely related Strongly-Interacting Massive Particle (SIMP) scenario, the ELDER predictions provide a physically motivated, well-defined target region, which will be almost entirely accessible to the next generation of searches for sub-GeV darkmatter and dark photons. We provide useful analytic approximations for various quantities of interest in the ELDER scenario, and discuss two simple renormalizable toy models which incorporate the required strong number-changing interactions among the ELDERs, as well as explicitly implement the coupling to electrons via the dark photon portal.

The large excess of DarkMatter observed in the Universe and its particle nature is one of the key problems yet to be solved in particle physics. Despite the extensive success of the Standard Model, it is not able to explain this excess, which instead might be due to yet unknown particles, such as Weakly Interacting Massive Particles, that could be produced at the Large Hadron Collider. This contribution will give an overview of different approaches to finding evidence for DarkMatter with the ATLAS experiment in $\\sqrt{s}=8~\\mathrm{TeV}$ Run-1 data.

In the Cold DarkMatter scenario, the DarkMatter particle candidate may be a Weakly Interacting Massive Particle (Wimp). Annihilation of two Wimps in local or cosmological structures would result in the production of a number of standard model particles such as photons, leptons and baryons which could be observed with the presently available or future experiments such as the Pamela or Glast satellites or the Cherenkov Telescopes. In this work we review the status-of-the-art of the theoretical and phenomenological studies about the possibility of indirect detection of signals coming from Wimp annihilation.

The astrophysical evidence of darkmatter provides some of the most compelling clues to the nature of physics beyond the Standard Model. From these clues, ATLAS has developed a broad and systematic search program for darkmatter production in LHC collisions. These searches are now entering their prime, with the LHC now colliding protons at the increased 13 TeV centre-of-mass energy and set to deliver much larger datasets than ever before. The results of these searches on the first 13 TeV data, their interpretation, and the design and possible evolution of the search program will be presented.

We investigate the possibility that a massive weakly interacting fermion simultaneously provides for a dominant component of the darkmatter relic density and an invisible decay width of the Higgs boson at the LHC. As a concrete model realizing such dynamics we consider the minimal walking...... technicolor, although our results apply more generally. Taking into account the constraints from the electroweak precision measurements and current direct searches for darkmatter particles, we find that such scenario is heavily constrained, and large portions of the parameter space are excluded....

We propose a novel darkmatter (DM) detection strategy for models with a nonminimal dark sector. The main ingredients in the underlying DM scenario are a boosted DM particle and a heavier dark sector state. The relativistic DM impinged on target material scatters off inelastically to the heavier state, which subsequently decays into DM along with lighter states including visible (standard model) particles. The expected signal event, therefore, accompanies a visible signature by the secondary cascade process associated with a recoiling of the target particle, differing from the typical neutrino signal not involving the secondary signature. We then discuss various kinematic features followed by DM detection prospects at large-volume neutrino detectors with a model framework where a dark gauge boson is the mediator between the standard model particles and DM.

We consider the possibility that the black-hole (BH) binary detected by LIGO may be a signature of darkmatter. Interestingly enough, there remains a window for masses 20M_{⊙}≲M_{bh}≲100M_{⊙} where primordial black holes (PBHs) may constitute the darkmatter. If two BHs in a galactic halo pass sufficiently close, they radiate enough energy in gravitational waves to become gravitationally bound. The bound BHs will rapidly spiral inward due to the emission of gravitational radiation and ultimately will merge. Uncertainties in the rate for such events arise from our imprecise knowledge of the phase-space structure of galactic halos on the smallest scales. Still, reasonable estimates span a range that overlaps the 2-53 Gpc^{-3} yr^{-1} rate estimated from GW150914, thus raising the possibility that LIGO has detected PBH darkmatter. PBH mergers are likely to be distributed spatially more like darkmatter than luminous matter and have neither optical nor neutrino counterparts. They may be distinguished from mergers of BHs from more traditional astrophysical sources through the observed mass spectrum, their high ellipticities, or their stochastic gravitational wave background. Next-generation experiments will be invaluable in performing these tests.

The existance of a new form of matter, DarkMatter, has been established by a large body of astrophysical measurements. The particle nature of DarkMatter is one of the most intriguing and important open issues in physics today. A review of searches for DarkMatter by the LHC experiments is presented

We consider the possibility that the darkmatter is coupled through its mass to a scalar field associated with the dark energy of the Universe. In order for such a field to play a role at the present cosmological distances, it must be effectively massless at galactic length scales. We discuss the effect of the field on the distribution of darkmatter in galaxy halos. We show that the profile of the distribution outside the galaxy core remains largely unaffected and the approximately flat rotation curves persist. The dispersion of the darkmatter velocity is enhanced by a potentially large factor relative to the case of zero coupling between dark energy and darkmatter. The counting rates in terrestrial darkmatter detectors are similarly enhanced. Existing bounds on the properties of darkmatter candidates can be extended to the coupled case, by taking into account the enhancement factor

The best particle candidates for non--baryonic cold darkmatter are reviewed, namely, neutralino, axion, axino and Majoron. These particles are considered in the context of cosmological models with the restrictions given by the observed mass spectrum of large scale structures, data on clusters of galaxies, age of the Universe etc.

On an empirical level, the most successful alternative to darkmatter in bound gravitational systems is the modified Newtonian dynamics, or MOND, proposed by Milgrom. Here I discuss the attempts to formulate MOND as a modification of General Relativity. I begin with a summary of the phenomenological

A simple way of explaining darkmatter without modifying known Standard Model physics is to require the existence of a hidden (dark) sector, which interacts with the visible one predominantly via gravity. We consider a hidden sector containing two stable particles charged under an unbroken U (1 )' gauge symmetry, hence featuring dissipative interactions. The massless gauge field associated with this symmetry, the dark photon, can interact via kinetic mixing with the ordinary photon. In fact, such an interaction of strength ε ˜10-9 appears to be necessary in order to explain galactic structure. We calculate the effect of this new physics on big bang nucleosynthesis and its contribution to the relativistic energy density at hydrogen recombination. We then examine the process of dark recombination, during which neutral dark states are formed, which is important for large-scale structure formation. Galactic structure is considered next, focusing on spiral and irregular galaxies. For these galaxies we modeled the darkmatter halo (at the current epoch) as a dissipative plasma of darkmatter particles, where the energy lost due to dissipation is compensated by the energy produced from ordinary supernovae (the core-collapse energy is transferred to the hidden sector via kinetic mixing induced processes in the supernova core). We find that such a dynamical halo model can reproduce several observed features of disk galaxies, including the cored density profile and the Tully-Fisher relation. We also discuss how elliptical and dwarf spheroidal galaxies could fit into this picture. Finally, these analyses are combined to set bounds on the parameter space of our model, which can serve as a guideline for future experimental searches.

We argue here that many (up to around 30 species) so far undetected Goldstone bosons could exist in nature, for example, associated to the spontaneous breaking of a horizontal global symmetry, provided the breaking scale is V >or approx. 10 10 GeV. Since Goldstone bosons do not generate r - 1 but spin-dependent r - 3 non-relativistic long-range potentials, the apparently most dramatic effect of massless bosons - new long-range forces competing with gravitation and electromagnetism - is easily avoidable (the Glashow-Weinberg-Salam breaking scale is enough). μ→eG and K→πG provide the most restrictive bounds and probably the only possibility to look for Goldstone bosons in laboratory. (author)

Imagine a scenario in which the dark energy forms via the condensation of darkmatter at some low redshift. The Compton wavelength therefore changes from small to very large at the transition, unlike quintessence or metamorphosis. We study cosmic microwave background (CMB), large scale structure, supernova and radio galaxy constraints on condensation by performing a four parameter likelihood analysis over the Hubble constant and the three parameters associated with Q, the condensate field: Ω Q , w f and z t (energy density and equation of state today, and redshift of transition). Condensation roughly interpolates between ΛCDM (for large z t ) and SCDM (low z t ) and provides a slightly better fit to the data than ΛCDM. We confirm that there is no degeneracy in the CMB between H and z t and discuss the implications of late-time transitions for the Lyman-α forest. Finally we discuss the nonlinear phase of both condensation and metamorphosis, which is much more interesting than in standard quintessence models

We consider the generalized Chaplygin gas (GCG) proposal for unification of dark energy and darkmatter and show that it admits an unique decomposition into dark energy and darkmatter components once phantomlike dark energy is excluded. Within this framework, we study structure formation and show that difficulties associated to unphysical oscillations or blowup in the matter power spectrum can be circumvented. Furthermore, we show that the dominance of dark energy is related to the time when energy density fluctuations start deviating from the linear δ∼a behavior

The seesaw mechanism in models with extra dimensions is shown to be generically consistent with a broad range of Majorana masses. The resulting democracy of scales implies that the seesaw mechanism can naturally explain the smallness of neutrino masses for an arbitrarily small right-handed neutrino mass. If the scales of the seesaw parameters are split, with two right-handed neutrinos at a high scale and one at a keV scale, one can explain the matter-antimatter asymmetry of the universe, as well as darkmatter. The darkmatter candidate, a sterile right-handed neutrino with mass of several keV, can account for the observed pulsar velocities and for the recent data from Chandra X-ray Observatory, which suggest the existence of a 5 keV sterile right-handed neutrino.

The question “What is the Universe made of?” is the longest outstanding problem in all of physics. Ordinary atoms only constitute 5% of the total, while the rest is of unknown composition. Already in 1933 Fritz Zwicky observed that the rapid motions of objects within clusters of galaxies were unexplained by the gravitation pull of luminous matter, and he postulated the existence of Dunkle Materie, or darkmatter. A variety of darkmatter candidates exist, including new fundamental particles already postulated in particle theories: axions and WIMPs (weakly interacting massive particles). Over the past 25 years, there has been a three pronged approach to WIMP detection: creating them at particle accelerators; searched for detection of astrophysical WIMPs scattering off of nuclei in underground detectors; and “indirect detection” of WIMP annihilation products (neutrinos, positrons, or photons). As yet the LHC has only placed bounds rather than finding discovery. For 13 years the DAMA experiment has proc...

Pure singlets are typically disfavored as darkmatter candidates, since they generically have a thermal relic abundance larger than the observed value. In this paper, we propose a new darkmatter mechanism called a ssimilation , which takes advantage of the baryon asymmetry of the universe to generate the correct relic abundance of singlet darkmatter. Through assimilation, darkmatter itself is efficiently destroyed, but darkmatter number is stored in new quasi-stable heavy states which carry the baryon asymmetry. The subsequent annihilation and late-time decay of these heavy states yields (symmetric) darkmatter as well as (asymmetric) standard model baryons. We study in detail the case of pure bino darkmatter by augmenting the minimal supersymmetric standard model with vector-like chiral multiplets. In the parameter range where this mechanism is effective, the LHC can discover long-lived charged particles which were responsible for assimilating darkmatter

This report contains discussions on the following topics: the strong CP problem; darkmatter axions; the cavity detector of galactic halo axions; and caustic rings in the density distribution of cold darkmatter halos

In this review, we focus on darkmatter production from thermal freeze-out with forbidden channels and SIMP processes. We show that forbidden channels can be dominant to produce darkmatter depending on the dark photon and / or dark Higgs mass compared to SIMP.

Various particle physics models suggest that, besides the (nearly) cold darkmatter that accounts for current observations, additional but sub-dominant dark relics might exist. These could be warm, hot, or even contribute as dark radiation. We present here a comprehensive study of two-component dark

This review discusses both experimental and theoretical aspects of searches for darkmatter at the LHC. An overview of the various experimental search channels is given, followed by a summary of the different theoretical approaches for predicting darkmatter signals. A special emphasis is placed on the interplay between LHC darkmatter searches and other kinds of darkmatter experiments, as well as among different types of LHC searches.

This review discusses both experimental and theoretical aspects of searches for darkmatter at the LHC. An overview of the various experimental search channels is given, followed by a summary of the different theoretical approaches for predicting darkmatter signals. A special emphasis is placed on the interplay between LHC darkmatter searches and other kinds of darkmatter experiments, as well as among different types of LHC searches.

We demonstrate that darkmatter particles gravitationally bound to the Earth can induce a characteristic nuclear recoil signal at low energies in direct detection experiments. The new spectral feature we predict can provide the ultimate smoking gun for darkmatter discovery for experiments...... with positive signal but unclear background. The new feature is universal, in that the ratio of bound over halo darkmatter event rates at detectors is independent of the darkmatter-nucleon cross section....

Darkmatter may be a thermal relic whose abundance is set by mutual annihilations among multiple species. Traditionally, this coannihilation scenario has been applied to weak scale darkmatter that is highly degenerate with other states. We show that coannihilation among states with split masses points to darkmatter that is exponentially lighter than the weak scale, down to the keV scale. We highlight the regime where darkmatter does not participate in the annihilations that dilute its numb...

There is by now compelling evidence that most of the matter in the universe is in the form of darkmatter, a form of matter quite different from the matter we experience in every day life. The gravitational effects of this darkmatter have been observed in many different ways but its true nature is still unknown. In most models darkmatter particles can annihilate with each other into standard model particles. The direct or indirect observation of such annihilation products could give important clues for the darkmatter puzzle. For signals from darkmatter annihilations to be detectable, typically high darkmatter densities are required. Massive objects, such as stars, can increase the local darkmatter density both via scattering off nucleons and by pulling in darkmatter gravitationally as the star forms. Darkmatter annihilations outside the star would give rise to gamma rays and this is discussed in the first paper. Furthermore darkmatter annihilations inside the star would deposit energy inside the star which, if abundant enough, could alter the stellar evolution. Aspects of this are investigated in the second paper. Finally, local darkmatter over densities formed in the early universe could still be around today; prospects of detecting gamma rays from such clumps are discussed in the third paper

We present measurements of the shape of the stellar line-of-sight velocity distribution out to two effective radii along the major axes of the four elliptical galaxies NGC 2434, 2663, 3706, and 5018. The velocity dispersion profiles are flat or decline gently with radius. We compare the data to the predictions of f = f(E, L(sub z)) axisymmetric models with and without darkmatter. Strong tangential anisotropy is ruled out at large radii. We conclude from our measurements that massive dark halos must be present in three of the four galaxies, while for the fourth galaxy (NGC 2663) the case is inconclusive.

We study the backreaction of free quantum fields on a flat Robertson-Walker spacetime. Apart from renormalization freedom, the vacuum energy receives contributions from both the trace anomaly and the thermal nature of the quantum state. The former represents a dynamical realisation of dark energy, while the latter mimics an effective darkmatter component. The semiclassical dynamics yield two classes of asymptotically stable solutions. The first reproduces the CDM model in a suitable regime. The second lacks a classical counterpart, but is in excellent agreement with recent observations. (orig.)

We study the backreaction of free quantum fields on a flat Robertson-Walker spacetime. Apart from renormalization freedom, the vacuum energy receives contributions from both the trace anomaly and the thermal nature of the quantum state. The former represents a dynamical realisation of dark energy, while the latter mimics an effective darkmatter component. The semiclassical dynamics yield two classes of asymptotically stable solutions. The first reproduces the CDM model in a suitable regime. The second lacks a classical counterpart, but is in excellent agreement with recent observations. (orig.)

This document summarises the potential of AMS in the indirect search for DarkMatter. Observations and cosmology indicate that the Universe may include a large amount of DarkMatter of unknown nature. A good candidate is the Ligthest Supersymmetric Particle in R-Parity conserving models. AMS offers a unique opportunity to study DarkMatter indirect signature in three spectra: gamma, antiprotons and positrons

I review the phenomenology of particle darkmatter, including the process of thermal freeze-out in the early universe, and the direct and indirect detection of WIMPs. I also describe some of the most popular particle candidates for darkmatter and summarize the current status of the quest to discover darkmatter's particle identity.

Studies of galaxy surveys in the context of the cold darkmatter paradigm have shown that the mass of the darkmatter halo and the total stellar mass are coupled through a function that varies smoothly with mass. Their average ratio M halo /M stars has a minimum of about 30 for galaxies with stellar masses near that of the Milky Way (approximately 5 × 10 10 solar masses) and increases both towards lower masses and towards higher masses. The scatter in this relation is not well known; it is generally thought to be less than a factor of two for massive galaxies but much larger for dwarf galaxies. Here we report the radial velocities of ten luminous globular-cluster-like objects in the ultra-diffuse galaxy NGC1052-DF2, which has a stellar mass of approximately 2 × 10 8 solar masses. We infer that its velocity dispersion is less than 10.5 kilometres per second with 90 per cent confidence, and we determine from this that its total mass within a radius of 7.6 kiloparsecs is less than 3.4 × 10 8 solar masses. This implies that the ratio M halo /M stars is of order unity (and consistent with zero), a factor of at least 400 lower than expected. NGC1052-DF2 demonstrates that darkmatter is not always coupled with baryonic matter on galactic scales.

Studies of galaxy surveys in the context of the cold darkmatter paradigm have shown that the mass of the darkmatter halo and the total stellar mass are coupled through a function that varies smoothly with mass. Their average ratio Mhalo/Mstars has a minimum of about 30 for galaxies with stellar masses near that of the Milky Way (approximately 5 × 1010 solar masses) and increases both towards lower masses and towards higher masses. The scatter in this relation is not well known; it is generally thought to be less than a factor of two for massive galaxies but much larger for dwarf galaxies. Here we report the radial velocities of ten luminous globular-cluster-like objects in the ultra-diffuse galaxy NGC1052–DF2, which has a stellar mass of approximately 2 × 108 solar masses. We infer that its velocity dispersion is less than 10.5 kilometres per second with 90 per cent confidence, and we determine from this that its total mass within a radius of 7.6 kiloparsecs is less than 3.4 × 108 solar masses. This implies that the ratio Mhalo/Mstars is of order unity (and consistent with zero), a factor of at least 400 lower than expected. NGC1052–DF2 demonstrates that darkmatter is not always coupled with baryonic matter on galactic scales.

It has been shown by many independent studies that the cold darkmatter scenario produces singular galactic dark halos, in strong contrast with observations. Possible remedies are that either the darkmatter is warm so that it has significant thermal motion or that the darkmatter has strong self-interactions. We combine these ideas to calculate the linear mass power spectrum and the spectrum of cosmic microwave background (CMB) fluctuations for self-interacting warm darkmatter. Our results indicate that such models have more power on small scales than is the case for the standard warm darkmatter model, with a CMB fluctuation spectrum which is nearly indistinguishable from standard cold darkmatter. This enhanced small-scale power may provide better agreement with the observations than does standard warm darkmatter. (c) 2000 The American Physical Society

Observations by the WMAP and PLANCK satellites have provided extraordinarily accurate observations on the densities of baryonic matter, darkmatter, and dark energy in the universe. These observations indicate that our universe is composed of approximately ve times as much darkmatter as baryonic matter. However, e orts to detect a particle responsible for the energy density of darkmatter have been unsuccessful. Theoretical models have indicated that a leading candidate for the darkmatter is the lightest supersymmetric particle, which may be stable due to a conserved R-parity. This darkmatter particle would still be capable of interacting with baryons via weak-force interactions in the early universe, a process which was found to naturally explain the observed relic abundance of darkmatter today. These residual annihilations can persist, albeit at a much lower rate, in the present universe, providing a detectable signal from darkmatter annihilation events which occur throughout the universe. Simulations calculating the distribution of darkmatter in our galaxy almost universally predict the galactic center of the Milky Way Galaxy (GC) to provide the brightest signal from darkmatter annihilation due to its relative proximity and large simulated darkmatter density. Recent advances in telescope technology have allowed for the rst multiwavelength analysis of the GC, with suitable e ective exposure, angular resolution, and energy resolution in order to detect darkmatter particles with properties similar to those predicted by the WIMP miracle. In this work, I describe ongoing e orts which have successfully detected an excess in -ray emission from the region immediately surrounding the GC, which is di cult to describe in terms of standard di use emission predicted in the GC region. While the jury is still out on any darkmatter interpretation of this excess, I describe several related observations which may indicate a darkmatter origin. Finally, I discuss the

It is argued that the lightest supersymmetric particle (LSP) emerging from the superstring theory is a mixture of neutral gauginos and matter fermions. Their mixing matrix is calculated in a plausible minimal low-energy model abstracted from the superstring and the composition of the LSP chi is exhibited. Its relic cosmological density is computed and it is found that it lies within a factor 2 of the critical density required for closure, over a wide range of possible input parameters. The flux of neutrinos from LSP annihilation in the Sun is computed and it is found that it straddles the upper bound from proton decay detectors. Acceptable fluxes are obtained if m chi is less than m/sub t/, in which case the superstring relic can have the critical density for a present Hubble expansion rate H 0 greater than or approximately equal to 50 km/s/Mpc only if m/sub t/ is greater than or approximately 40 GeV. 25 refs., 3 figs., 1 tab

We investigate the phenomenology of a simplified model of flavoured DarkMatter (DM), with a dark fermionic flavour triplet coupling to the left-handed SU(2) L quark doublets via a scalar mediator. The DM-quark coupling matrix is assumed to constitute the only new source of flavour and CP violation, following the hypothesis of Dark Minimal Flavour Violation. We analyse the constraints from LHC searches, from meson mixing data in the K, D, and B d,s meson systems, from thermal DM freeze-out, and from direct detection experiments. Our combined analysis shows that while the experimental constraints are similar to the DMFV models with DM coupling to right-handed quarks, the multitude of couplings between DM and the SM quark sector resulting from the SU(2) L structure implies a richer phenomenology and significantly alters the resulting impact on the viable parameter space.

We consider the hypothesis that darkmatter and dark energy consists of ultra-light self-interacting scalar particles. It is found that the Klein-Gordon equation with only two free parameters (mass and self-coupling) on a Schwarzschild background, at the galactic length-scales has the solution which corresponds to Bose-Einstein condensate, behaving as darkmatter, while the constant solution at supra-galactic scales can explain dark energy.

Coloured relics servived after hadronization might have given birth to darkmatter and dark energy. Theoretical ideas to solve mystery of cosmic acceleration, its origin and its status with reference to recent past are of much interest and are being proposed by many workers. In the present paper, we present a critical review of work done to understand the earliest appearance of darkmatter and dark energy in the scenario of primordial quark gluon plasma (QGP) phase after Big Bang.

We study the possibility of late forming darkmatter, where a scalar field, previously trapped in a metastable state by thermal or finite density effects, goes through a phase transition near the era matter-radiation equality and begins to oscillate about its true minimum. Such a theory is motivated generally if the dark energy is of a similar form, but has not yet made the transition to darkmatter, and, in particular, arises automatically in recently considered theories of neutrino dark energy. If such a field comprises the present darkmatter, the matter power spectrum typically shows a sharp break at small, presently nonlinear scales, below which power is highly suppressed and previously contained acoustic oscillations. If, instead, such a field forms a subdominant component of the total darkmatter, such acoustic oscillations may imprint themselves in the linear regime.

Full Text Available If there are a plethora of axions in nature, they may have a complicated potential and create an axion landscape. We study a possibility that one of the axions is so light that it is cosmologically stable, explaining the observed darkmatter density. In particular we focus on a case in which two (or more shift-symmetry breaking terms conspire to make the axion sufficiently light at the potential minimum. In this case the axion has a flat-bottomed potential. In contrast to the case in which a single cosine term dominates the potential, the axion abundance as well as its isocurvature perturbations are significantly suppressed. This allows an axion with a rather large mass to serve as darkmatter without fine-tuning of the initial misalignment, and further makes higher-scale inflation to be consistent with the scenario.

The most natural region of cosmologically compatible darkmatter relic density in terms of low fine-tuning in a minimal supersymmetric standard model with nonuniversal gaugino masses is the so called bulk annihilation region. We study this region in a simple and predictive SUSY- GUT model of nonuniversal gaugino masses, where the latter transform as a combination of singlet plus a nonsinglet representation of the GUTgroup SU(5). The model prediction for the direct darkmatter detection rates is well below the present CDMS and XENON100 limits, but within the reach of a future 1Ton XENON experiment. The most interesting and robust model prediction is an indirect detection signal of hard positron events, which resembles closely the shape of the observed positron spectrum from the PAMELA experiment. (author)

We propose that the stability of darkmatter is ensured by a discrete subgroup of the U(1){sub B-L} gauge symmetry, Z{sub 2}(B-L). We introduce a set of chiral fermions charged under the U(1){sub B-L} in addition to the right-handed neutrinos, and require the anomaly-cancellation conditions associated with the U(1){sub B-L} gauge symmetry. We find that the possible number of fermions and their charges are tightly constrained, and that non-trivial solutions appear when at least five additional chiral fermions are introduced. The Fermat theorem in the number theory plays an important role in this argument. Focusing on one of the solutions, we show that there is indeed a good candidate for darkmatter, whose stability is guaranteed by Z{sub 2}(B-L).

We propose that the stability of darkmatter is ensured by a discrete subgroup of the U(1) B-L gauge symmetry, Z 2 (B-L). We introduce a set of chiral fermions charged under the U(1) B-L in addition to the right-handed neutrinos, and require the anomaly-cancellation conditions associated with the U(1) B-L gauge symmetry. We find that the possible number of fermions and their charges are tightly constrained, and that non-trivial solutions appear when at least five additional chiral fermions are introduced. The Fermat theorem in the number theory plays an important role in this argument. Focusing on one of the solutions, we show that there is indeed a good candidate for darkmatter, whose stability is guaranteed by Z 2 (B-L).

We propose and study a new class of superconducting detectors that are sensitive to O(meV) electron recoils from darkmatter-electron scattering. Such devices could detect darkmatter as light as the warm dark-matter limit, m(X)≳1 keV. We compute the rate of dark-matter scattering off of free electrons in a (superconducting) metal, including the relevant Pauli blocking factors. We demonstrate that classes of darkmatter consistent with terrestrial and cosmological or astrophysical constraints could be detected by such detectors with a moderate size exposure.

Research concerned with the existence and nature of darkmatter is examined. The first evidence of darkmatter discovered by Oort in 1932 during the study of galactic rotation and observations by Bahcall in 1984 using tracer stars are discussed. Stars, gas, dust, rocks, white dwarfs, neutron stars, black holes, and red and brown dwarfs are investigated as possible forms of darkmatter. The date reveal that gas, dust, neutron stars, black holes, rocks, and comets can not be darkmatter; however, brown, red, or white dwarfs could be possible forms of darkmatter

We provide further details on a recent proposal addressing the nature of the dark sectors in cosmology and demonstrate that all current observations related to DarkMatter can be explained by the presence of a heavy spin-2 particle. Massive spin-2 fields and their gravitational interactions are uniquely described by ghost-free bimetric theory, which is a minimal and natural extension of General Relativity. In this setup, the largeness of the physical Planck mass is naturally related to extremely weak couplings of the heavy spin-2 field to baryonic matter and therefore explains the absence of signals in experiments dedicated to DarkMatter searches. It also ensures the phenomenological viability of our model as we confirm by comparing it with cosmological and local tests of gravity. At the same time, the spin-2 field possesses standard gravitational interactions and it decays universally into all Standard Model fields but not into massless gravitons. Matching the measured DM abundance together with the requirement of stability constrains the spin-2 mass to be in the 1 to 100 TeV range.

Full Text Available Several independent astronomical observations in different wavelength bands reveal the existence of much larger quantities of matter than what we would deduce from assuming a solar mass to light ratio. They are very high velocities of individual galaxies within clusters of galaxies, higher than expected rotation rates of stars in the outer regions of galaxies, 21 cm line studies indicative of increasing mass to light ratios with radius in the halos of spiral galaxies, hot gaseous X-ray emitting halos around many elliptical galaxies, and clusters of galaxies requiring a much larger component of unseen mass for the hot gas to be bound. The level of gravitational attraction needed for the spatial distribution of galaxies to evolve from the small perturbations implied by the very slightly anisotropic cosmic microwave background radiation to its current web-like configuration requires much more mass than is observed across the entire electromagnetic spectrum. Distorted shapes of galaxies and other features created by gravitational lensing in the images of many astronomical objects require an amount of darkmatter consistent with other estimates. The unambiguous detection of darkmatter and more recently evidence for dark energy has positioned astronomy at the frontier of fundamental physics as it was in the 17th century.

Various particle physics models suggest that, besides the (nearly) cold darkmatter that accounts for current observations, additional but sub-dominant dark relics might exist. These could be warm, hot, or even contribute as dark radiation. We present here a comprehensive study of two-component darkmatter scenarios, where the first component is assumed to be cold, and the second is a non-cold thermal relic. Considering the cases where the non-cold darkmatter species could be either a fermion or a boson, we derive consistent upper limits on the non-cold dark relic energy density for a very large range of velocity dispersions, covering the entire range from dark radiation to cold darkmatter. To this end, we employ the latest Planck Cosmic Microwave Background data, the recent BOSS DR11 and other Baryon Acoustic Oscillation measurements, and also constraints on the number of Milky Way satellites, the latter of which provides a measure of the suppression of the matter power spectrum at the smallest scales due to the free-streaming of the non-cold darkmatter component. We present the results on the fraction f ncdm of non-cold darkmatter with respect to the total darkmatter for different ranges of the non-cold darkmatter masses. We find that the 2σ limits for non-cold darkmatter particles with masses in the range 1–10 keV are f ncdm ≤0.29 (0.23) for fermions (bosons), and for masses in the 10–100 keV range they are f ncdm ≤0.43 (0.45), respectively.

Various particle physics models suggest that, besides the (nearly) cold darkmatter that accounts for current observations, additional but sub-dominant dark relics might exist. These could be warm, hot, or even contribute as dark radiation. We present here a comprehensive study of two-component darkmatter scenarios, where the first component is assumed to be cold, and the second is a non-cold thermal relic. Considering the cases where the non-cold darkmatter species could be either a fermion or a boson, we derive consistent upper limits on the non-cold dark relic energy density for a very large range of velocity dispersions, covering the entire range from dark radiation to cold darkmatter. To this end, we employ the latest Planck Cosmic Microwave Background data, the recent BOSS DR11 and other Baryon Acoustic Oscillation measurements, and also constraints on the number of Milky Way satellites, the latter of which provides a measure of the suppression of the matter power spectrum at the smallest scales due to the free-streaming of the non-cold darkmatter component. We present the results on the fraction f {sub ncdm} of non-cold darkmatter with respect to the total darkmatter for different ranges of the non-cold darkmatter masses. We find that the 2σ limits for non-cold darkmatter particles with masses in the range 1–10 keV are f {sub ncdm}≤0.29 (0.23) for fermions (bosons), and for masses in the 10–100 keV range they are f {sub ncdm}≤0.43 (0.45), respectively.

What is the quantity and composition of material in the Universe This is one of the most fundamental questions we can ask about the Universe, and its answer bears on a number of important issues including the formation of structure in the Universe, and the ultimate fate and the earliest history of the Universe. Moreover, answering this question could lead to the discovery of new particles, as well as shedding light on the nature of the fundamental interactions. At present, only a partial answer is at hand: Most of the material in the Universe does not give off detectable radiation, i.e., is dark;'' the darkmatter associated with bright galaxies contributes somewhere between 10% and 30% of the critical density (by comparison luminous matter contributes less than 1%); baryonic matter contributes between 1.1% and 12% of critical. The case for the spatially-flat, Einstein-de Sitter model is supported by three compelling theoretical arguments--structure formation, the temporal Copernican principle, and inflation--and by some observational data. If {Omega} is indeed unity--or even just significantly greater than 0.1--then there is a strong case for a Universe comprised of nonbaryonic matter. There are three well motivated particle dark-matter candidates: an axion of mass 10{sup {minus}6} eV to 10{sup {minus}4} eV; a neutralino of mass 10 GeV to about 3 TeV; or a neutrino of mass 20 eV to 90 eV. All three possibilities can be tested by experiments that are either being planned or are underway. 63 refs.

What is the quantity and composition of material in the Universe? This is one of the most fundamental questions we can ask about the Universe, and its answer bears on a number of important issues including the formation of structure in the Universe, and the ultimate fate and the earliest history of the Universe. Moreover, answering this question could lead to the discovery of new particles, as well as shedding light on the nature of the fundamental interactions. At present, only a partial answer is at hand: Most of the material in the Universe does not give off detectable radiation, i.e., is ''dark;'' the darkmatter associated with bright galaxies contributes somewhere between 10% and 30% of the critical density (by comparison luminous matter contributes less than 1%); baryonic matter contributes between 1.1% and 12% of critical. The case for the spatially-flat, Einstein-de Sitter model is supported by three compelling theoretical arguments--structure formation, the temporal Copernican principle, and inflation--and by some observational data. If Ω is indeed unity--or even just significantly greater than 0.1--then there is a strong case for a Universe comprised of nonbaryonic matter. There are three well motivated particle dark-matter candidates: an axion of mass 10 -6 eV to 10 -4 eV; a neutralino of mass 10 GeV to about 3 TeV; or a neutrino of mass 20 eV to 90 eV. All three possibilities can be tested by experiments that are either being planned or are underway. 63 refs

What is the quantity and composition of material in the universe This is one of the most fundamental questions we can ask about the universe, and its answer bears on a number of important issues including the formation of structure in the universe, and the ultimate fate and the earliest history of the universe. Moreover, answering this question could lead to the discovery of new particles, as well as shedding light on the nature of the fundamental interactions. At present, only a partial answer is at hand: most of the material in the universe does not give off detectable radiation, i.e., is dark;'' the darkmatter associated with bright galaxies contributes somewhere between 10% and 30% of the critical density (by comparison luminous matter contributes less than 1%); baryonic matter contributes between 1.1% and 12% of critical. The case for the spatially-flat, Einstein-de Sitter model is supported by three compelling theoretical arguments -- structure formation, the temporal Copernican principle, and inflation -- and by some observational data. If {Omega} is indeed unity--or even just significantly greater than 0.1--then there is a strong case for a universe comprised of nonbaryonic matter. There are three well motivated particle dark-matter candidates: an axion of mass 10{sup {minus}6} eV to 10{sup {minus}4} eV; a neutralino of mass 10 GeV to about 3 TeV; or a neutrino of mass 20 eV to 90 eV. All three possibilities can be tested by experiments that are either being planned or are underway. 71 refs., 6 figs.

The low mass (10 GeV scale) darkmatter is indicted and favored by several recent darkmatter direct detection experimental results, such as DAMA and CoGeNT. In this talk, we discuss some aspects of the low mass darkmatter. We study the indirect detection of darkmatter through neutrino flux from their annihilation in the center of the Sun, in a class of models where the darkmatter-nucleon spin-independent interactions break the isospin symmetry. The indirect detection using neutrino telescopes can impose a relatively stronger constraint and brings tension to such explanation, if the darkmatter self-annihilation is dominated by heavy quarks or τ-lepton final states. The asymmetric darkmatter doesn't suffer the constraints from the indirect detection results. We propose a model of asymmetric darkmatter where the matter and darkmatter share the common origin, the asymmetries in both the matter and darkmatter sectors are simultaneously generated through leptogenesis, and we explore how this model can be tested in direct search experiments.

We study the interplay of flavor and darkmatter phenomenology for models of flavored darkmatter interacting with quarks. We allow an arbitrary flavor structure in the coupling of darkmatter with quarks. This coupling is assumed to be the only new source of violation of the Standard Model flavor symmetry extended by a U(3) χ associated with the darkmatter. We call this ansatz Dark Minimal Flavor Violation (DMFV) and highlight its various implications, including an unbroken discrete symmetry that can stabilize the darkmatter. As an illustration we study a Dirac fermionic darkmatter χ which transforms as triplet under U(3) χ , and is a singlet under the Standard Model. The darkmatter couples to right-handed down-type quarks via a colored scalar mediator with a coupling. We identify a number of ''flavor-safe'' scenarios for the structure of which are beyond Minimal Flavor Violation. Also, for darkmatter and collider phenomenology we focus on the well-motivated case of b-flavored darkmatter. Furthermore, the combined flavor and darkmatter constraints on the parameter space of turn out to be interesting intersections of the individual ones. LHC constraints on simplified models of squarks and sbottoms can be adapted to our case, and monojet searches can be relevant if the spectrum is compressed

In [1], Kallosh and Linde drew attention to a new family of superconformal inflationary potentials, subsequently called α-attractors [2]. The α-attractor family can interpolate between a large class of inflationary models. It also has an important theoretical underpinning within the framework of supergravity. We demonstrate that the α-attractors have an even wider appeal since they may describe darkmatter and perhaps even dark energy. The darkmatter associated with the α-attractors, which we call α-darkmatter (αDM), shares many of the attractive features of fuzzy darkmatter, with V (φ) = ½ m 2 φ 2 , while having none of its drawbacks. Like fuzzy darkmatter, αDM can have a large Jeans length which could resolve the cusp-core and substructure problems faced by standard cold darkmatter. αDM also has an appealing tracker property which enables it to converge to the late-time darkmatter asymptote, ( w ) ≅ 0, from a wide range of initial conditions. It thus avoids the enormous fine-tuning problems faced by the m 2 φ 2 potential in describing darkmatter.

In [1], Kallosh and Linde drew attention to a new family of superconformal inflationary potentials, subsequently called α-attractors [2]. The α-attractor family can interpolate between a large class of inflationary models. It also has an important theoretical underpinning within the framework of supergravity. We demonstrate that the α-attractors have an even wider appeal since they may describe darkmatter and perhaps even dark energy. The darkmatter associated with the α-attractors, which we call α-darkmatter (αDM), shares many of the attractive features of fuzzy darkmatter, with V (φ) = ½ m {sup 2}φ{sup 2}, while having none of its drawbacks. Like fuzzy darkmatter, αDM can have a large Jeans length which could resolve the cusp-core and substructure problems faced by standard cold darkmatter. αDM also has an appealing tracker property which enables it to converge to the late-time darkmatter asymptote, ( w ) ≅ 0, from a wide range of initial conditions. It thus avoids the enormous fine-tuning problems faced by the m {sup 2}φ{sup 2} potential in describing darkmatter.

Mirror matter is a darkmatter candidate. In this paper, we reexamine the linear regime of density perturbation growth in a universe containing mirror darkmatter. Taking adiabatic scale-invariant perturbations as the input, we confirm that the resulting processed power spectrum is richer than for the more familiar cases of cold, warm and hot darkmatter. The new features include a maximum at a certain scale λ max , collisional damping below a smaller characteristic scale λ S ' , with oscillatory perturbations between the two. These scales are functions of the fundamental parameters of the theory. In particular, they decrease for decreasing x, the ratio of the mirror plasma temperature to that of the ordinary. For x∼0.2, the scale λ max becomes galactic. Mirror darkmatter therefore leads to bottom-up large scale structure formation, similar to conventional cold darkmatter, for x(less-or-similar sign)0.2. Indeed, the smaller the value of x, the closer mirror darkmatter resembles standard cold darkmatter during the linear regime. The differences pertain to scales smaller than λ S ' in the linear regime, and generally in the nonlinear regime because mirror darkmatter is chemically complex and to some extent dissipative. Lyman-α forest data and the early reionization epoch established by WMAP may hold the key to distinguishing mirror darkmatter from WIMP-style cold darkmatter

In the present Universe visible and darkmatter contribute comparable energy density although they have different properties. This phenomenon can be explained if the darkmatter relic density, originating from a darkmatter asymmetry, is fully determined by the baryon asymmetry. Thus the darkmatter mass is not arbitrary; rather, it becomes predictive. We realize this scenario in baryon (lepton) number conserving models where two or more neutral singlet scalars decay into two or three baryonic (leptonic) darkmatter scalars, and also decay into quarks (leptons) through other on-shell and/or off-shell exotic scalar bilinears. The produced baryon (lepton) asymmetries in the darkmatter scalar and in the standard model quarks (leptons) are thus equal and opposite. The darkmatter mass can be predicted in a range from a few GeV to a few TeV, depending on the baryon (lepton) numbers of the decaying scalars and the darkmatter scalar. The darkmatter scalar can interact with the visible matter through the exchange of the standard model Higgs boson, opening a window for the darkmatter direct detection experiments. These models also provide testable predictions in the searches for the exotic scalar bilinears at LHC.

What is the quantity and composition of material in the Universe? This is one of the most fundamental questions we can ask about the Universe, and its answer bears on a number of important issues including the formation of structure in the Universe, and the ultimate fate and the earliest history of the Universe. Moreover, answering this question could lead to the discovery of new particles, as well as shedding light on the nature of the fundamental interactions. At present, only a partial answer is at hand. Most of the radiation in the Universe does not give off detectable radiation; it is dark. The darkmatter associated with bright galaxies contributes somewhere between 10 and 30 percent of the critical density; baryonic matter contributes between 1.1 and 12 percent of the critical. The case for the spatially flat, Einstein-de Sitter model is supported by three compelling theoretical arguments - structure formation, the temporal Copernican principle, and inflation - and by some observational data. If Omega is indeed unity, or even just significantly greater than 0.1, then there is a strong case for a Universe comprised of nonbaryonic matter. There are three well motivated particle darkmatter candidates: an axion of mass 10 (exp -6) eV to 10 (exp -4) eV; a neutrino of mass 10 GeV to about 3 TeV; or a neutrino of mass 20 eV to 90 eV. All three possibilities can be tested by experiments that are either planned or are underway.

A survey is presented of the current understanding of darkmatter invoked by astrophysical theory and cosmology. Einstein's equivalence principle asserts that local measurements cannot distinguish a system at rest in a gravitational field from one that is in uniform acceleration in empty space. Recent test-methods for the equivalence principle are presently discussed as bases for testing of darkmatter scenarios involving the long-range forces between either baryonic or nonbaryonic darkmatter and ordinary matter.

Self-interacting darkmatter (SIDM) is a hypothetical form of darkmatter (DM), characterized by relatively strong (compared to the weak interaction strength) self-interactions (SIs), which has been proposed to resolve a number of issues concerning tensions between simulations and observations at the galactic or smaller scales. We review here some recent developments discussed at the 14th Marcel Grossmann Meeting (MG14), paying particular attention to restrictions on the SIDM (total) cross-section from using novel observables in merging galactic structures, as well as the rôle of SIDM on the Milky Way halo and its central region. We report on some interesting particle-physics inspired SIDM models that were discussed at MG14, namely the glueball DM, and a right-handed neutrino DM (with mass of a few tens of keV, that may exist in minimal extensions of the standard model (SM)), interacting among themselves via vector bosons mediators in the dark sector. A detailed phenomenology of the latter model on galactic scales, as well as the potential role of the right handed neutrinos in alleviating some of the small-scale cosmology problems, namely the discrepancies between observations and numerical simulations within standard ΛCDM and ΛWDM cosmologies are reported.

We study asymmetric darkmatter (ADM) in the context of the minimal (fraternal) twin Higgs solution to the little hierarchy problem, with a twin sector with gauged SU(3)^{'}×SU(2)^{'}, a twin Higgs doublet, and only third-generation twin fermions. Naturalness requires the QCD^{'} scale Λ_{QCD}^{'}≃0.5-20 GeV, and that t^{'} is heavy. We focus on the light b^{'} quark regime, m_{b^{'}}≲Λ_{QCD}^{'}, where QCD^{'} is characterized by a single scale Λ_{QCD}^{'} with no light pions. A twin baryon number asymmetry leads to a successful darkmatter (DM) candidate: the spin-3/2 twin baryon, Δ^{'}∼b^{'}b^{'}b^{'}, with a dynamically determined mass (∼5Λ_{QCD}^{'}) in the preferred range for the DM-to-baryon ratio Ω_{DM}/Ω_{baryon}≃5. Gauging the U(1)^{'} group leads to twin atoms (Δ^{'}-τ^{'}[over ¯] bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo properties. Direct detection signatures satisfy current bounds, at times modified by dark form factors.

Composite darkmatter is a natural setting for implementing inelastic darkmatter - the O(100 keV) mass splitting arises from spin-spin interactions of constituent fermions. In models where the constituents are charged under an axial U(1) gauge symmetry that also couples to the Standard Model quarks, darkmatter scatters inelastically off Standard Model nuclei and can explain the DAMA/LIBRA annual modulation signal. This article describes the early Universe cosmology of a minimal implementation of a composite inelastic darkmatter model where the darkmatter is a meson composed of a light and a heavy quark. The synthesis of the constituent quarks into dark hadrons results in several qualitatively different configurations of the resulting darkmatter composition depending on the relative mass scales in the system.

The early universe could feature multiple reheating events, leading to jumps in the visible sector entropy density that dilute both particle asymmetries and the number density of frozen-out states. In fact, late time entropy jumps are usually required in models of Affleck-Dine baryogenesis, which typically produces an initial particle-antiparticle asymmetry that is much too large. An important consequence of late time dilution, is that a smaller darkmatter annihilation cross section is needed to obtain the observed darkmatter relic density. For cosmologies with high scale baryogenesis, followed by radiation-dominated darkmatter freeze-out, we show that the perturbative unitarity mass bound on thermal relic darkmatter is relaxed to 10{sup 10} GeV. We proceed to study superheavy asymmetric darkmatter models, made possible by a sizable entropy injection after darkmatter freeze-out, and identify how the Affleck-Dine mechanism would generate the baryon and dark asymmetries.

The early universe could feature multiple reheating events, leading to jumps in the visible sector entropy density that dilute both particle asymmetries and the number density of frozen-out states. In fact, late time entropy jumps are usually required in models of Affleck-Dine baryogenesis, which typically produces an initial particle-antiparticle asymmetry that is much too large. An important consequence of late time dilution, is that a smaller darkmatter annihilation cross section is needed to obtain the observed darkmatter relic density. For cosmologies with high scale baryogenesis, followed by radiation-dominated darkmatter freeze-out, we show that the perturbative unitarity mass bound on thermal relic darkmatter is relaxed to 10 10 GeV. We proceed to study superheavy asymmetric darkmatter models, made possible by a sizable entropy injection after darkmatter freeze-out, and identify how the Affleck-Dine mechanism would generate the baryon and dark asymmetries.

We investigate new and unusual signals that arise in theories where darkmatter is asymmetric and carries a net antibaryon number, as may occur when the darkmatter abundance is linked to the baryon abundance. Antibaryonic darkmatter can cause induced nucleon decay by annihilating visible baryons through inelastic scattering. These processes lead to an effective nucleon lifetime of 10 29 -10 32 yrs in terrestrial nucleon decay experiments, if baryon number transfer between visible and dark sectors arises through new physics at the weak scale. The possibility of induced nucleon decay motivates a novel approach for direct detection of cosmic darkmatter in nucleon decay experiments. Monojet searches (and related signatures) at hadron colliders also provide a complementary probe of weak-scale dark-matter-induced baryon number violation. Finally, we discuss the effects of baryon-destroying darkmatter on stellar systems and show that it can be consistent with existing observations.

Recent breakthroughs in cosmology reveal that a quarter of the Universe is composed of darkmatter, but the microscopic identity of darkmatter remains a deep mystery. I review recent progress in resolving this puzzle, focusing on two well-motivated classes of darkmatter candidates: weakly interacting massive particles (WIMPs) and superWIMPs. These possibilities have similar motivations: they exist in the same well-motivated particle physics models, the observed darkmatter relic density emerges naturally and darkmatter particles have mass around 100 GeV, the energy scale identified as interesting over 70 years ago by Fermi. At the same time, they have widely varying implications for direct and indirect darkmatter searches, particle colliders, Big Bang nucleosynthesis, the cosmic microwave background, and halo profiles and structure formation. If WIMPs or superWIMPs are a significant component of darkmatter, we will soon be entering a golden era in which darkmatter will be studied through diverse probes at the interface of particle physics, astroparticle physics and cosmology. I outline a programme of darkmatter studies for each of these scenarios and discuss the prospects for identifying darkmatter in the coming years. (topical review)

Recent astronomical data strongly suggest that a significant part of the darkmatter content of the Local Group and Virgo Supercluster is not incorporated into the galaxy halos and forms diffuse components of these galaxy clusters. A portion of the particles from these components may penetrate the Milky Way and make an extragalactic contribution to the total darkmatter containment of our Galaxy. We find that the particles of the diffuse component of the Local Group are apt to contribute ∼12% to the total darkmatter density near Earth. The particles of the extragalactic darkmatter stand out because of their high speed (∼600 km s –1 ), i.e., they are much faster than the galactic darkmatter. In addition, their speed distribution is very narrow (∼20 km s –1 ). The particles have an isotropic velocity distribution (perhaps, in contrast to the galactic darkmatter). The extragalactic darkmatter should provide a significant contribution to the direct detection signal. If the detector is sensitive only to the fast particles (v > 450 km s –1 ), then the signal may even dominate. The density of other possible types of the extragalactic darkmatter (for instance, of the diffuse component of the Virgo Supercluster) should be relatively small and comparable with the average darkmatter density of the universe. However, these particles can generate anomaly high-energy collisions in direct darkmatter detectors.

The axion, a hypothetical elementary particle, emerged from a compelling solution to the Strong-CP Problem in QCD. Subsequently, the axion was recognized to be a good Cold DarkMatter candidate. Although dark-matter axions have only feeble couplings to matter and radiation, these axions may be detected through resonant conversion of axions into microwave photons in a high-Q cavity threaded by a strong static magnetic field. This technique is at present the only means whereby dark-matter axions with plausible couplings may be detected at the required sensitivity. This talk describes recent results from the Axion DarkMatter Experiment (ADMX), now the world's most sensitive search for axions. There will also be a short overview of the ADMX upgrade, which promises sensitivity to even the more feebly coupled darkmatter axions even should they make up only a minority fraction of the local darkmatter halo

We consider theories in which there exists a nontrivial coupling between the darkmatter sector and the sector responsible for the acceleration of the Universe. Such theories can possess an adiabatic regime in which the quintessence field always sits at the minimum of its effective potential, which is set by the local darkmatter density. We show that if the coupling strength is much larger than gravitational, then the adiabatic regime is always subject to an instability. The instability, which can also be thought of as a type of Jeans instability, is characterized by a negative sound speed squared of an effective coupled darkmatter/dark energy fluid, and results in the exponential growth of small scale modes. We discuss the role of the instability in specific coupled cold darkmatter and mass varying neutrino models of dark energy and clarify for these theories the regimes in which the instability can be evaded due to nonadiabaticity or weak coupling.

Recent experiments have brought for the first time under a strong experimental basis that the total density of the Universe is Wo = 1.02 ± 0.02. We have for the first time a cosmic agreement, namely matter density WM = 0.27 ± 0.04 and dark energy density WL = 0.73 ± 0.04 add up precisely to Wo ! WM + WL. On the other hand ordinary hadronic matter (quarks and leptons) determined by the Big Bang Nucleo-synthesis (BBN) is also firmly set to WBBN = 0.044 ± 0.004. About 100 years after Einstein's birth we know experimentally the identity of less than 5% of what the Universe is made of, the remaining > 95% escaping to us completely. An enormous effort is being made at LHC in order to discover SUSY particles. SUSY is an almost necessity of elementary particle physics. The fact that such particles may also account for the observed non baryonic darkmatter is either a big coincidence or a big hint. If such SUSY particles indeed exist, they must have been...

We consider current observational constraints on the electromagnetic charge of darkmatter. The velocity dependence of the scattering cross section through the photon gives rise to qualitatively different constraints than standard darkmatter scattering through massive force carriers. In particular, recombination epoch observations of darkmatter density perturbations require that ε, the ratio of the darkmatter to electronic charge, is less than 10 -6 for m X =1 GeV, rising to ε -4 for m X =10 TeV. Though naively one would expect that darkmatter carrying a charge well below this constraint could still give rise to large scattering in current direct detection experiments, we show that charged darkmatter particles that could be detected with upcoming experiments are expected to be evacuated from the Galactic disk by the Galactic magnetic fields and supernova shock waves and hence will not give rise to a signal. Thus darkmatter with a small charge is likely not a source of a signal in current or upcoming darkmatter direct detection experiments.

Stars account for only about 0.5% of the content of the Universe; the bulk of the Universe is optically dark. The dark side of the Universe is comprised of: at least 0.1% light neutrinos; 3.5% ± 1% baryons; 29% ± 4% cold darkmatter; and 66% ± 6% dark energy. Now that we have characterized the dark side of the Universe, the challenge is to understand it. The critical questions are: (1) What form do the dark baryons take? (2) What is (are) the constituent(s) of the cold darkmatter? (3) What is the nature of the mysterious dark energy that is causing the Universe to speed up

DarkMatter might be an accidentally stable baryon of a new confining gauge interaction. We extend previous studies exploring the possibility that the DM is made of dark quarks heavier than the dark confinement scale. The resulting phenomenology contains new unusual elements: a two-stage DM cosmology (freeze-out followed by dark condensation), a large DM annihilation cross section through recombination of dark quarks (allowing to fit the positron excess). Light dark glue-balls are relatively long lived and give extra cosmological effects; DM itself can remain radioactive.

A progress report of the ORPHEUS darkmatter experiment in the Bern Underground Laboratory is presented. A description of the ORPHEUS detector and its sensitivity to WIMPs is given. The detector will consist of 1 to 2 kg Sn granules operating in a magnetic field of approximately 320 G and at a temperature of 50 mK. In the first phase, the detector will be read out by conventional pickup coils, followed by a second phase with SQUID loops. Preliminary results on background and radioactivity measurements are shown. (orig.)

We have recently examined a large number of points in the parameter space of the phenomenological MSSM, the 19-dimensional parameter space of the CP-conserving MSSM with Minimal Flavor Violation. We determined whether each of these points satisfied existing experimental and theoretical constraints. This analysis provides insight into general features of the MSSM without reference to a particular SUSY breaking scenario or any other assumptions at the GUT scale. This study opens up new possibilities for SUSY phenomenology both in colliders and in astrophysical experiments. Here we shall discuss the implications of this analysis relevant to the study of darkmatter.

For half a century, astrophysicists have suspected that there is more to the Universe than meets the eye. With the gravitational pull between bodies depending on their masses, the relative motion of different parts of the Universe is a pointer to the masses involved. In the 1930s, Fritz Zwicky made the first speculations about so - called 'darkmatter', and Jan Oort discovered that there was not enough visible material surrounding the sun to explain the motion of stars around our own galaxy

The ArDM experiment, a 1 ton liquid argon TPC/Calorimeter, is designed for the detection of darkmatter particles which can scatter off the spinless argon nucleus, producing nuclear recoils. These events will be discerned by their light to charge ratio, as well as the time structure of the scintillation light. The experiment is presently under construction and commissioning on surface at CERN. Cryogenic operation and light detection performance was recently confirmed in a test run of the full 1 ton liquid argon target under purely calorimetric operation and with a prototype light readout system. This note describes the experimental concept, the main detector components and presents some first results.

The Tully-Fisher relation is used to probe darkmatter (DM) in the optical regions of spiral galaxies. By establishing it at several different isophotal radii in an appropriate sample of 58 galaxies with good B-band photometry and rotation curves, it is shown that some of its attributes (such as scatter, residuals, nonlinearity, and bias) dramatically decrease moving from the disk edge inward. This behavior challenges any mass model which assumes no DM or a luminosity-independent DM mass fraction interior to the optical radius of spiral galaxies. 58 refs

We consider the generic possibility that the Universe's energy budget includes some form of relativistic or semi-relativistic dark radiation (DR) with nongravitational interactions with standard model (SM) particles. Such dark radiation may consist of SM singlets or a nonthermal, energetic component of neutrinos. If such DR is created at a relatively recent epoch, it can carry sufficient energy to leave a detectable imprint in experiments designed to search for very weakly interacting particles: darkmatter and underground neutrino experiments. We analyze this possibility in some generality, assuming that the interactive dark radiation is sourced by late decays of an unstable particle, potentially a component of darkmatter, and considering a variety of possible interactions between the dark radiation and SM particles. Concentrating on the sub-GeV energy region, we derive constraints on different forms of DR using the results of the most sensitive neutrino and darkmatter direct detection experiments. In particular, for interacting dark radiation carrying a typical momentum of ˜30 MeV /c , both types of experiments provide competitive constraints. This study also demonstrates that non-standard sources of neutrino emission (e.g., via darkmatter decay) are capable of creating a "neutrino floor" for darkmatter direct detection that is closer to current bounds than is expected from standard neutrino sources.

If cold darkmatter consists of particles, these must be non-interacting and non-relativistic by definition. In most cold darkmatter models however, darkmatter particles inherit a non-vanishing velocity dispersion from interactions in the early universe, a velocity that redshifts with cosmic expansion but certainly remains non-zero. In this article, we place model-independent constraints on the darkmatter temperature to mass ratio, whose square root determines the darkmatter velocity dispersion. We only assume that darkmatter particles decoupled kinetically while non-relativistic, when galactic scales had not entered the horizon yet, and that their momentum distribution has been Maxwellian since that time. Under these assumptions, using cosmic microwave background and matter power spectrum observations, we place upper limits on the temperature to mass ratio of cold darkmatter today (away from collapsed structures). These limits imply that the present cold darkmatter velocity dispersion has to be smaller than 54 m/s. Cold darkmatter has to be quite cold, indeed

In this paper we investigate light darkmatter scenarios where annihilation to Standard Model particles at tree-level is kinematically forbidden. In such cases annihilation can be aided by massive Standard Model-like species, called assisters , in the initial state that enhances the available phase space opening up novel tree-level processes. We investigate the feasibility of such non-standard assisted annihilation processes to reproduce the observed relic density of darkmatter. We present a simple scalar darkmatter-scalar assister model where this is realised. We find that if the darkmatter and assister are relatively degenerate the required relic density can be achieved for a keV-MeV scale darkmatter. We briefly discuss the cosmological constraints on such darkmatter scenarios.

If darkmatter decays into electrons and positrons, it can affect Galactic radio emissions and the local cosmic ray fluxes. We propose a new, more general analysis of constraints on darkmatter. The constraints can be obtained for any decaying darkmatter model by convolving the specific darkmatter decay spectrum with a response function. We derive this response function from full-sky radio surveys at 408 MHz, 1.42 GHz and 23 GHz, as well as from the positron flux recently reported by PAMELA. We discuss the influence of astrophysical uncertainties on the response function, such as from propagation and from the profiles of the darkmatter and the Galactic magnetic field. As an application, we find that some widely used darkmatter decay scenarios can be ruled out under modest assumptions. (orig.)

While a suitable candidate particle for darkmatter (DM) has yet to be discovered, it is possible one will be found by experiments currently investigating physics on the weak scale. If discovered on that energy scale, the darkmatter will likely be producible in significant quantities at colliders like the LHC, allowing the properties of and underlying physical model characterizing the darkmatter to be precisely determined. I assume that the darkmatter will be produced as one of the decay products of a new massive resonance related to physics beyond the Standard Model, and using the energy distributions of the associated visible decay products, develop techniques for determining the symmetry protecting these potential darkmatter candidates from decaying into lighter Standard Model (SM) particles and to simultaneously measure the masses of both the darkmatter candidate and the particle from which it decays.

The prediction of neutralino darkmatter is generally regarded as one of the successes of the Minimal Supersymmetric Standard Model (MSSM). However the successful regions of parameter space allowed by WMAP and collider constraints are quite restricted. We discuss fine-tuning with respect to both darkmatter and Electroweak Symmetry Breaking (EWSB) and explore regions of MSSM parameter space with non-universal gaugino and third family scalar masses in which neutralino darkmatter may be implemented naturally. In particular allowing non-universal gauginos opens up the bulk region that allows Bino annihilation via t-channel slepton exchange, leading to ``supernatural darkmatter'' corresponding to no fine-tuning at all with respect to darkmatter. By contrast we find that the recently proposed ``well tempered neutralino'' regions involve substantial fine-tuning of MSSM parameters in order to satisfy the darkmatter constraints, although the fine tuning may be ameliorated if several annihilation channels act simu...

If darkmatter decays into electrons and positrons, it can affect Galactic radio emissions and the local cosmic ray fluxes. We propose a new, more general analysis of constraints on darkmatter. The constraints can be obtained for any decaying darkmatter model by convolving the specific darkmatter decay spectrum with a response function. We derive this response function from full-sky radio surveys at 408 MHz, 1.42 GHz and 23 GHz, as well as from the positron flux recently reported by PAMELA. We discuss the influence of astrophysical uncertainties on the response function, such as from propagation and from the profiles of the darkmatter and the Galactic magnetic field. As an application, we find that some widely used darkmatter decay scenarios can be ruled out under modest assumptions. (orig.)

We discuss asymmetric or symmetric darkmatter candidate in the supersymmetric Dirac leptogenesis scenario. By introducing a singlet superfield coupling to right-handed neutrinos, the overabundance problem of darkmatter can be evaded and various possibilities for darkmatter candidate arise. If the singlino is the lightest supersymmetric particle (LSP), it becomes naturally asymmetric darkmatter. On the other hand, the right-handed sneutrino is a symmetric darkmatter candidate whose relic density can be determined by the usual thermal freeze-out process. The conventional neutralino or gravitino LSP can be also a darkmatter candidate as its non-thermal production from the right-handed sneutrino can be controlled appropriately. In our scenario, the late-decay of heavy supersymmetric particles mainly produces the right-handed sneutrino and neutrino which is harmless to the standard prediction of the Big-Bang Nucleosynthesis

The axion is a hypothetical particle which would explain why QCD is approximately T-conserving, and is also an excellent Cold DarkMatter candidate. It should be possible to make a clean theoretical prediction relating the darkmatter density in axions and the axion mass (under reasonable assumptions about inflation). But the axion's early-Universe dynamics, which establish its density as darkmatter, are unexpectedly rich in a way which is only starting to yield to quantitative numerical study.

The darkmatter search and darkmatter detection is very importance project in Particle Physics, Astrophysics and Cosmology. The paper introduces the current status of the darkmatter search in the world and points out that the development of detector with larger scale, lower threshold, very low radioactive background and building of underground laboratory is important developing direction. So far, there is no such detector and underground laboratory in our county. We should change such situation as soon as possible. (authors)

The lightest neutralino in minimal supersymmetry (SUSY) and other SUSY models is considered as a dark-matter candidate. The phenomenological and cosmological properties of the neutralino and some experimental constraints are discussed. A bino-like neutralino emerges as the most natural dark-matter candidate for a plausible range of parameters. Direct methods for dark-matter searches and relevant experiments are also reviewed

Recent experimental data confirms that approximately one quarter of the universe consists of cold darkmatter. Particle theories provide natural candidates for this darkmatter in the form of either Axions or Weakly Interacting Massive Particles (WIMPs). A growing body of experiments is aimed at direct or indirect detection of particle darkmatter. I summarize the current status of these experiments and offer projections of their future sensitivity

In the context of the relationship between physics of cosmological darkmatter and symmetry of elementary particles, a wide list of darkmatter candidates is possible. New symmetries provide stability of different new particles and their combination can lead to a multicomponent darkmatter. The pattern of symmetry breaking involves phase transitions in the very early Universe, extending the list of candidates by topological defects and even primordial nonlinear structures.

We propose a hybrid model of universe for galaxy formation, that is, an Einstein- de Sitter universe dominated by two-component darkmatter: massive neutrinos and cold darkmatter. In this hybrid model, the first luminous objects are dwarf galaxies. The neutrino density fluctuations produce large-scale high density and low density regions, which consequently evolve to superclusters of galaxies and voids, respectively. Dwarf galaxies are formed preferentially in supercluster regions. In voids, the formation of dwarf galaxies is fairly suppressed by diffuse UV flux from QSOs, and instead a number of expanding clouds are born, which produce Lyα forest as seen in QSO spectra. Ordinary galaxies are expected to form as aggregations of dwarf galaxies. In this model, some galaxies are born also in voids, and they tend to evolve to spiral galaxies. Additionally, if the same number of globular clusters are formed in a dwarf, the specific globular cluster frequencies are expected to be much larger in ellipticals than in spirals. (author)

We consider a model where both dark energy and darkmatter originate from the coupling of a scalar field with a non-canonical kinetic term to, both, a metric measure and a non-metric measure. An interacting dark energy/darkmatter scenario can be obtained by introducing an additional scalar that can produce non constant vacuum energy and associated variations in darkmatter. The phenomenology is most interesting when the kinetic term of the additional scalar field is ghost-type, since in this case the dark energy vanishes in the early universe and then grows with time. This constitutes an ''inverse quintessence scenario'', where the universe starts from a zero vacuum energy density state, instead of approaching it in the future.

We consider a model where both dark energy and darkmatter originate from the coupling of a scalar field with a non-canonical kinetic term to, both, a metric measure and a non-metric measure. An interacting dark energy/darkmatter scenario can be obtained by introducing an additional scalar that can produce non constant vacuum energy and associated variations in darkmatter. The phenomenology is most interesting when the kinetic term of the additional scalar field is ghost-type, since in this case the dark energy vanishes in the early universe and then grows with time. This constitutes an ''inverse quintessence scenario'', where the universe starts from a zero vacuum energy density state, instead of approaching it in the future

Non-Local Astrophysics: DarkMatter, Dark Energy and Physical Vacuum highlights the most significant features of non-local theory, a highly effective tool for solving many physical problems in areas where classical local theory runs into difficulties. The book provides the fundamental science behind new non-local astrophysics, discussing non-local kinetic and generalized hydrodynamic equations, non-local parameters in several physical systems, darkmatter, dark energy, black holes and gravitational waves. Devoted to the solution of astrophysical problems from the position of non-local physics Provides a solution for darkmatter and dark energy Discusses cosmological aspects of the theory of non-local physics Includes a solution for the problem of the Hubble Universe expansion, and of the dependence of the orbital velocity from the center of gravity

We propose a new thermal freeze-out mechanism for ultraheavy darkmatter. Darkmatter coannihilates with a lighter unstable species that is nearby in mass, leading to an annihilation rate that is exponentially enhanced relative to standard weakly interactive massive particles. This scenario destabilizes any potential darkmatter candidate. In order to remain consistent with astrophysical observations, our proposal necessitates very long-lived states, motivating striking phenomenology associated with the late decays of ultraheavy darkmatter, potentially as massive as the scale of grand unified theories, M_{GUT}∼10^{16} GeV.

There is overwhelming indirect evidence that darkmatter exists, however, the darkmatter particle has not yet been directly detected in laboratory experiments. In order to be able to identify the rare darkmatter interactions with the target nuclei, such instruments have to feature a very low threshold and an extremely low radioactive background. They are therefore installed in underground laboratories to reduce cosmic ray backgrounds. I will review the status of direct darkmatter searches and will discuss the perspectives for the future.

We consider a class of fermionic darkmatter candidates that are charged under both the SU(2) L and U(1) Y gauge interactions. Such a darkmatter is stringently restricted by the darkmatter direct detection experiments, since the Z-boson exchange processes induce too large darkmatter-nucleus elastic scattering cross sections. Effects of ultraviolet (UV) physics, however, split it into two Majorana fermions to evade the constraint. These effects may be probed by means of the darkmatter-nucleus scattering via the Higgs-boson exchange process, as well as the electric dipole moments induced by the darkmatter and its SU(2) L partner fields. In this Letter, we evaluate them with effective operators that describe the UV-physics effects. It turns out that the constraints coming from the experiments for the quantities have already restricted the darkmatters with hypercharge Y≥3/2. Future experiments have sensitivities to probe this class of darkmatter candidates, and may disfavor the Y≥1 cases if no signal is observed. In this case, only the Y=0 and 1/2 cases may be the remaining possibilities for the SU(2) L charged fermionic darkmatter candidates.

Cosmological nucleosynthesis calculations imply that there should be both non-baryonic and baryonic darkmatter. Recent data suggest that some of the non-baryonic darkmatter must be "hot" (i.e. massive neutrinos) and there may also be evidence for "cold" darkmatter (i.e. WIMPs). If the baryonic darkmatter resides in galactic halos, it is likely to be in the form of compact objects (i.e. MACHOs) and these would probably be the remnants of a first generation of pregalactic or protogalactic P...

We study darkmatter production by decaying topological defects, in particular cosmic strings. In topological defect or ''top-down'' (TD) scenarios, the darkmatter injection rate varies as a power law with time with exponent p−4. We find a formula in closed form for the yield for all p < 3/2, which accurately reproduces the solution of the Boltzmann equation. We investigate two scenarios (p = 1, p = 7/6) motivated by cosmic strings which decay into TeV-scale states with a high branching fraction into darkmatter particles. For darkmatter models annihilating either by s-wave or p-wave, we find the regions of parameter space where the TD model can account for the darkmatter relic density as measured by Planck. We find that topological defects can be the principal source of darkmatter, even when the standard freeze-out calculation under-predicts the relic density and hence can lead to potentially large ''boost factor'' enhancements in the darkmatter annihilation rate. We examine darkmatter model-independent limits on this scenario arising from unitarity and discuss example model-dependent limits coming from indirect darkmatter search experiments. In the four cases studied, the upper bound on Gμ for strings with an appreciable channel into TeV-scale states is significantly more stringent than the current Cosmic Microwave Background limits

DarkMatter composes almost 25% of our Universe, but its identity is still unknown which makes it a large challenge for current fundamental physics. A lot of approaches are used to discover the identity of DarkMatter and one of them, collider searches, are discussed in this talk. The latest results on DarkMatter search at ATLAS using 2015 and 2016 data are presented. Results from searches for new physics in the events with final states containing large missing transverse energy + X (photons, jets, boson) are shown. Higgs to invisible and dijet searches are used in sense of complementarity to constrain properties of DarkMatter.

Sterile neutrino darkmatter, a popular alternative to the WIMP paradigm, has generally been studied in non-supersymmetric setups. If the underlying theory is supersymmetric, we find that several interesting and novel darkmatter features can arise. In particular, in scenarios of freeze-in production of sterile neutrino darkmatter, its superpartner, the sterile sneutrino, can play a crucial role in early Universe cosmology as the dominant source of cold, warm, or hot darkmatter, or of a subdominant relativistic population of sterile neutrinos that can contribute to the effective number of relativistic degrees of freedom Neff during big bang nucleosynthesis.

Massive gravity theories have been developed as viable IR modifications of gravity motivated by dark energy and the problem of the cosmological constant. On the other hand, modified gravity and modified darkmatter theories were developed with the aim of solving the problems of standard cold darkmatter at galactic scales. Here we propose to adapt the framework of ghost-free massive bigravity theories to reformulate the problem of darkmatter at galactic scales. We investigate a promising alternative to darkmatter called dipolar darkmatter (DDM) in which two different species of darkmatter are separately coupled to the two metrics of bigravity and are linked together by an internal vector field. We show that this model successfully reproduces the phenomenology of darkmatter at galactic scales (i.e. MOND) as a result of a mechanism of gravitational polarisation. The model is safe in the gravitational sector, but because of the particular couplings of the matter fields and vector field to the metrics, a ghost in the decoupling limit is present in the darkmatter sector. However, it might be possible to push the mass of the ghost beyond the strong coupling scale by an appropriate choice of the parameters of the model. Crucial questions to address in future work are the exact mass of the ghost, and the cosmological implications of the model

We investigate different neutrino signals from the decay of darkmatter particles to determine the prospects for their detection, and more specifically if any spectral signature can be disentangled from the background in present and future neutrino observatories. If detected, such a signal could bring an independent confirmation of the darkmatter interpretation of the dramatic rise in the positron fraction above 10 GeV recently observed by the PAMELA satellite experiment and offer the possibility of distinguishing between astrophysical sources and darkmatter decay or annihilation. In combination with other signals, it may also be possible to distinguish among different darkmatter decay channels. (orig.)

We investigate different neutrino signals from the decay of darkmatter particles to determine the prospects for their detection, and more specifically if any spectral signature can be disentangled from the background in present and future neutrino observatories. If detected, such a signal could bring an independent confirmation of the darkmatter interpretation of the dramatic rise in the positron fraction above 10 GeV recently observed by the PAMELA satellite experiment and offer the possibility of distinguishing between astrophysical sources and darkmatter decay or annihilation. In combination with other signals, it may also be possible to distinguish among different darkmatter decay channels. (orig.)

It has recently been pointed out that the 511 keV emission line detected by integral/SPI from the bulge of our galaxy could be explained by annihilations of light darkmatter particles into e + e - . If such a signature is confirmed, then one might expect a conflict with the interpretation of very high energy gamma rays if they also turn out to be due to darkmatter annihilations. Here, we propose a way to accommodate the existence of both signals being produced by darkmatter annihilations through the existence of two stable (neutral) darkmatter particles, as is possible in theories inspired from N=2 supersymmetry

Recent results from a dark-matter experiment in Italy suggest that the elusive weakly interacting massive particle or WIMP has finally been detected - but a rival experimental collaboration in the US disagrees. The controversy surrounding evidence for the discovery of ''darkmatter'' particles has heated up following two conflicting talks given at a conference at the end of February. The papers were presented at the 4th International Symposium on Sources and Detection of DarkMatter/Energy in the Universe held in Marina del Ray, California. For almost 70 years astronomers have known that dust, gas and other ordinary matter cannot account for almost 90% of the mass of many galaxies. The galaxies must contain other ''dark'' matter to explain the orbital motions of stars around their centres. Many astrophysicists, cosmologists and particle physicists have conjectured that this seemingly empty space could be populated by a dense body of massive, but very weakly interacting, particles called WIMPs. Such particles would then provide the gravitational fields needed to keep the stars moving as observed. Since the results of the first experimental efforts to detect these particles were published in 1987, literally dozens of experiments have been performed around the world. Two of the most sensitive experiments to date are the DAMA experiment at the Gran Sasso laboratory in Italy, and the CDMS experiment at Stanford University in the US. The DAMA collaboration - which includes physicists from the University of Rome Tor Vergata, the University of Rome La Sapienza and the Chinese Academy in Beijing - has been searching for WIMPs for several years using a large array of sodium-iodide detectors located 1400 m below ground. The CDMS experiment uses cryogenic detectors and is located just 10 m underground. The collaboration includes researchers from several centres in the US and Russia. Assuming that they do exist, a WIMP will occasionally strike a nucleus in the detector material

Avignone, Frank T. [Department of Physics and Astronomy, University of South Carolina, Columbia, SC (United States)

2000-04-01

Recent results from a dark-matter experiment in Italy suggest that the elusive weakly interacting massive particle or WIMP has finally been detected - but a rival experimental collaboration in the US disagrees. The controversy surrounding evidence for the discovery of ''darkmatter'' particles has heated up following two conflicting talks given at a conference at the end of February. The papers were presented at the 4th International Symposium on Sources and Detection of DarkMatter/Energy in the Universe held in Marina del Ray, California. For almost 70 years astronomers have known that dust, gas and other ordinary matter cannot account for almost 90% of the mass of many galaxies. The galaxies must contain other ''dark'' matter to explain the orbital motions of stars around their centres. Many astrophysicists, cosmologists and particle physicists have conjectured that this seemingly empty space could be populated by a dense body of massive, but very weakly interacting, particles called WIMPs. Such particles would then provide the gravitational fields needed to keep the stars moving as observed. Since the results of the first experimental efforts to detect these particles were published in 1987, literally dozens of experiments have been performed around the world. Two of the most sensitive experiments to date are the DAMA experiment at the Gran Sasso laboratory in Italy, and the CDMS experiment at Stanford University in the US. The DAMA collaboration - which includes physicists from the University of Rome Tor Vergata, the University of Rome La Sapienza and the Chinese Academy in Beijing - has been searching for WIMPs for several years using a large array of sodium-iodide detectors located 1400 m below ground. The CDMS experiment uses cryogenic detectors and is located just 10 m underground. The collaboration includes researchers from several centres in the US and Russia. Assuming that they do exist, a WIMP will occasionally

We suggest that two-to-two darkmatter fusion may be the relaxation process that resolves the small-scale structure problems of the cold collisionless darkmatter paradigm. In order for the fusion cross section to scale correctly across many decades of astrophysical masses from dwarf galaxies to galaxy clusters, we require the fractional binding energy released to be greater than vn∼(10−(2−3))n, where n=1, 2 depends on local dark sector chemistry. The size of the dark-sector interaction cross...

We study the cosmological consequences of codecaying dark matter—a recently proposed mechanism for depleting the density of darkmatter through the decay of nearly degenerate particles. A generic prediction of this framework is an early darkmatter dominated phase in the history of the Universe, that results in the enhanced growth of darkmatter perturbations on small scales. We compute the duration of the early matter dominated phase and show that the perturbations are robust against washout...

We study the interplay of flavor and darkmatter phenomenology for models of flavored darkmatter interacting with quarks. We allow an arbitrary flavor structure in the coupling of darkmatter with quarks. This coupling is assumed to be the only new source of violation of the Standard Model flavor symmetry extended by a $U(3)_\\chi$ associated with the darkmatter. We call this ansatz Dark Minimal Flavor Violation (DMFV) and highlight its various implications, including an unbroken discrete symmetry that can stabilize the darkmatter. As an illustration we study a Dirac fermionic darkmatter $\\chi$ which transforms as triplet under $U(3)_\\chi$, and is a singlet under the Standard Model. The darkmatter couples to right-handed down-type quarks via a colored scalar mediator $\\phi$ with a coupling $\\lambda$. We identify a number of "flavor-safe" scenarios for the structure of $\\lambda$ which are beyond Minimal Flavor Violation. For darkmatter and collider phenomenology we focus on the well-motivated case of $b$-...

Reheating in string compactifications is generically driven by the decay of the lightest modulus which produces Standard Model particles, darkmatter and light hidden sector degrees of freedom that behave as dark radiation. This common origin allows us to find an interesting correlation between darkmatter and dark radiation. By combining present upper bounds on the effective number of neutrino species N eff with lower bounds on the reheating temperature as a function of the darkmatter mass m DM from Fermi data, we obtain strong constraints on the (N eff , m DM )-plane. Most of the allowed region in this plane corresponds to non-thermal scenarios with Higgsino-like darkmatter. Thermal darkmatter can be allowed only if N eff tends to its Standard Model value. We show that the above situation is realised in models with perturbative moduli stabilisation where the production of dark radiation is unavoidable since bulk closed string axions remain light and do not get eaten up by anomalous U(1)s

Unveiling the nature of darkmatter and dark energy is one of the main tasks of particle physics and cosmology in the 21st century. We first present an overview of the history and current status of research in cosmology, at the same time emphasizing the new challenges in particle physics. Then we focus on the scientific issues of dark energy, darkmatter and anti-matter, and review the recent progress made in these fields. Finally, we discuss the prospects for future research on the experimental probing of darkmatter and dark energy in China. (authors)

Darkmatter is one of the major problems encountered by modern cosmology and astrophysics, resisting the efforts of both theoreticians and experimentalists. The problem itself is easy to state: many indirect astrophysical measurements indicate that the mass contained in the Universe seems to be dominated by a new type of matter which has never been directly seen yet, this is why it is called darkmatter. This hypothesis of darkmatter being made of new particles is of great interest for particle physicists, whose theories provide many candidates: darkmatter is one of the major topics of astro-particle physics. This work focuses on searching darkmatter in the form of new particles, more precisely to indirect detection, i.e. the search of particles produced by darkmatter annihilation rather than darkmatter particles themselves. In this framework, I will present the studies I have been doing in the field of cosmic rays physics (particularly cosmic ray sources), in several collaborations. In particular, the study of the antimatter component of cosmic rays can give relevant information about darkmatter. The last chapter is dedicated to my teaching activities

We study an extension of the Standard Model (SM) in which two copies of the SM scalar SU(2) doublet which do not acquire a Vacuum Expectation Value (VEV), and hence are inert, are added to the scalar sector. We allow for CP-violation in the inert sector, where the lightest inert state is protected from decaying to SM particles through the conservation of a Z 2 symmetry. The lightest neutral particle from the inert sector, which has a mixed CP-charge due to CP-violation, is hence a DarkMatter (DM) candidate. We discuss the new regions of DM relic density opened up by CP-violation, and compare our results to the CP-conserving limit and the Inert Doublet Model (IDM). We constrain the parameter space of the CP-violating model using recent results from the Large Hadron Collider (LHC) and DM direct and indirect detection experiments.

This book brings together reviews from leading international authorities on the developments in the study of darkmatter and dark energy, as seen from both their cosmological and particle physics side. Studying the physical and astrophysical properties of the dark components of our Universe is a crucial step towards the ultimate goal of unveiling their nature. The work developed from a doctoral school sponsored by the Italian Society of General Relativity and Gravitation. The book starts with a concise introduction to the standard cosmological model, as well as with a presentation of the theory of linear perturbations around a homogeneous and isotropic background. It covers the particle physics and cosmological aspects of darkmatter and (dynamical) dark energy, including a discussion of how modified theories of gravity could provide a possible candidate for dark energy. A detailed presentation is also given of the possible ways of testing the theory in terms of cosmic microwave background, galaxy redshift su...

In this review we first present a general formalism to study the growth of darkmatter perturbations in the presence of interactions between darkmatter(DM) and dark energy(DE). We also study the signature of such interaction on the temperature anisotropies of the large scale cosmic microwave background (CMB). We find that the effect of such interaction has significant signature on both the growth of darkmatter structure and the late Integrated Sachs Wolfe effect(ISW). We further discuss the potential possibility to detect the coupling by cross-correlating CMB maps with tracers of the large scale structure. We finally confront this interacting model with WMAP 5-year data as well as other data sets. We find that in the 1σ range, the constrained coupling between dark sectors can solve the coincidence problem.

We investigate unbound darkmatter particles in halos by tracing particle trajectories in a simulation run to the far future (a = 100). We find that the traditional sum of kinetic and potential energies is a very poor predictor of which darkmatter particles will eventually become unbound from halos. We also study the mass fraction of unbound particles, which increases strongly towards the edges of halos, and decreases significantly at higher redshifts. We discuss implications for darkmatter detection experiments, precision calibrations of the halo mass function, the use of baryon fractions to constrain dark energy, and searches for intergalactic supernovae.

We consider the prospects for multiple darkmatter direct detection experiments to determine if the interactions of a darkmatter candidate are isospin-violating. We focus on theoretically well-motivated examples of isospin-violating darkmatter (IVDM), including models in which darkmatter interactions with nuclei are mediated by a dark photon, a Z , or a squark. We determine that the best prospects for distinguishing IVDM from the isospin-invariant scenario arise in the cases of dark photon-or Z -mediated interactions, and that the ideal experimental scenario would consist of large exposure xenon- and neon-based detectors. If such models just evade current direct detection limits, then one could distinguish such models from the standard isospin-invariant case with two detectors with of order 100 ton-year exposure.

The prediction of neutralino darkmatter is generally regarded as one of the successes of the Minimal Supersymmetric Standard Model (MSSM). However the successful regions of parameter space allowed by WMAP and collider constraints are quite restricted. We discuss fine-tuning with respect to both darkmatter and Electroweak Symmetry Breaking (EWSB) and explore regions of MSSM parameter space with non-universal gaugino and third family scalar masses in which neutralino darkmatter may be implemented naturally. In particular allowing non-universal gauginos opens up the bulk region that allows Bino annihilation via t-channel slepton exchange, leading to 'supernatural darkmatter' corresponding to no fine-tuning at all with respect to darkmatter. By contrast we find that the recently proposed 'well tempered neutralino' regions involve substantial fine-tuning of MSSM parameters in order to satisfy the darkmatter constraints, although the fine tuning may be ameliorated if several annihilation channels act simultaneously. Although we have identified regions of 'supernatural darkmatter' in which there is no fine tuning to achieve successful darkmatter, the usual MSSM fine tuning to achieve EWSB always remains

One of the simplest models of darkmatter is where a scalar singlet field S comprises some or all of the darkmatter and interacts with the standard model through an vertical bar H vertical bar S-2(2) coupling to the Higgs boson. We update the present limits on the model from LHC searches for

The status of the scalar field or Bose condensate darkmatter model is presented. Results about the solitonic behavior in collision of structures is presented as a possible explanation to the recent-possibly-solitonic behavior in the bullet cluster merger. Some estimates about the possibility to simulate the bullet cluster under the Bose Condensate darkmatter model are indicated.

The prediction of neutralino darkmatter is generally regarded as one of the successes of the Minimal Supersymmetric Standard Model (MSSM). However the successful regions of parameter space allowed by WMAP and collider constraints are quite restricted. We discuss fine-tuning with respect to both darkmatter and Electroweak Symmetry Breaking (EWSB) and explore regions of MSSM parameter space with non-universal gaugino and third family scalar masses in which neutralino darkmatter may be implemented naturally. In particular allowing non-universal gauginos opens up the bulk region that allows Bino annihilation via t-channel slepton exchange, leading to ``supernatural darkmatter'' corresponding to no fine-tuning at all with respect to darkmatter. By contrast we find that the recently proposed ``well tempered neutralino'' regions involve substantial fine-tuning of MSSM parameters in order to satisfy the darkmatter constraints, although the fine tuning may be ameliorated if several annihilation channels act simultaneously. Although we have identified regions of ``supernatural darkmatter'' in which there is no fine tuning to achieve successful darkmatter, the usual MSSM fine tuning to achieve EWSB always remains.

Abstract: We derive the evolution of the energy deposition in the intergalactic medium (IGM) by darkmatter (DM) decays/annihilations for both sterile neutrinos and light darkmatter (LDM) particles. At z > 200 sterile neutrinos transfer a fraction f_abs~0.5 of their rest mass energy into the IGM;

Darkmatter pair production at high energy colliders may leave observable signatures in the energy and momentum spectra of the objects recoiling against the darkmatter. We use LEP data on monophoton events with large missing energy to constrain the coupling of darkmatter to electrons. Within a large class of models, our limits are complementary to and competitive with limits on darkmatter annihilation and on WIMP-nucleon scattering from indirect and direct searches. Our limits, however, do not suffer from systematic and astrophysical uncertainties associated with direct and indirect limits. For example, we are able to rule out light (< or approx. 10 GeV) thermal relic darkmatter with universal couplings exclusively to charged leptons. In addition, for darkmatter mass below about 80 GeV, LEP limits are stronger than Fermi constraints on annihilation into charged leptons in dwarf spheroidal galaxies. Within its kinematic reach, LEP also provides the strongest constraints on the spin-dependent direct detection cross section in models with universal couplings to both quarks and leptons. In such models the strongest limit is also set on spin-independent scattering for darkmatter masses below ∼4 GeV. Throughout our discussion, we consider both low energy effective theories of darkmatter, as well as several motivated renormalizable scenarios involving light mediators.

"The 70-year effort to unravel the mysteries of darkmatter just got a big boost from some very puny galaxies. In the pas few years, a score of dwarf galaxies have been discovered hanging about the fringes of the Milky way. Now new measurements of the few stars int hese dwarfs reveal them to be dark mater distilleries, with upwards of 1'000 times more dark than normal matter." (3 pages)

A simple and elegant mechanism is proposed to resolve the problem of having a light scalar mediator for self-interacting darkmatter and the resulting disruption to the cosmic microwave background (CMB) at late times by the former's enhanced Sommerfeld production and decay. The crucial idea is to have Dirac neutrinos with the conservation of U(1) lepton number extended to the dark sector. The simplest scenario consists of scalar or fermion darkmatter with unit lepton number accompanied by a ...

The nature of darkmatter is one of the most pressing questions in particle physics. Yet all our present knowledge of the dark sector to date comes from its gravitational interactions with astrophysical systems. Moreover, astronomical results still have immense potential to constrain the particle properties of darkmatter. We introduce a simple 2D parameter space which classifies models in terms of a particle physics interaction strength and a characteristic astrophysical scale on which new p...

Most darkmatter models set the darkmatter relic density by some interaction with Standard Model particles. Such models generally assume the existence of Standard Model particles early on, with the darkmatter relic density a later consequence of those interactions. Perhaps a more compelling assumption is that darkmatter is not part of the Standard Model sector and a population of darkmatter too is generated at the end of inflation. This democratic assumption about initial conditions does not necessarily provide a natural value for the darkmatter relic density, and furthermore superficially leads to too much entropy in the dark sector relative to ordinary matter. We address the latter issue by the late decay of heavy particles produced at early times, thereby associating the darkmatter relic density with the lifetime of a long-lived state. This paper investigates what it would take for this scenario to be compatible with observations in what we call Flooded DarkMatter (FDM) models and discusses several interesting consequences. One is that darkmatter can be very light and furthermore, light darkmatter is in some sense the most natural scenario in FDM as it is compatible with larger couplings of the decaying particle. A related consequence is that the decay of the field with the smallest coupling and hence the longest lifetime dominates the entropy and possibly the matter content of the Universe, a principle we refer to as “Maximum Baroqueness”. We also demonstrate that the dark sector should be colder than the ordinary sector, relaxing the most stringent free-streaming constraints on light darkmatter candidates. We will discuss the potential implications for the core-cusp problem in a follow-up paper. The FDM framework will furthermore have interesting baryogenesis implications. One possibility is that darkmatter is like the baryon asymmetry and both are simultaneously diluted by a late entropy dump. Alternatively, FDM is compatible with an elegant

Most darkmatter models set the darkmatter relic density by some interaction with Standard Model particles. Such models generally assume the existence of Standard Model particles early on, with the darkmatter relic density a later consequence of those interactions. Perhaps a more compelling assumption is that darkmatter is not part of the Standard Model sector and a population of darkmatter too is generated at the end of inflation. This democratic assumption about initial conditions does not necessarily provide a natural value for the darkmatter relic density, and furthermore superficially leads to too much entropy in the dark sector relative to ordinary matter. We address the latter issue by the late decay of heavy particles produced at early times, thereby associating the darkmatter relic density with the lifetime of a long-lived state. This paper investigates what it would take for this scenario to be compatible with observations in what we call Flooded DarkMatter (FDM) models and discusses several interesting consequences. One is that darkmatter can be very light and furthermore, light darkmatter is in some sense the most natural scenario in FDM as it is compatible with larger couplings of the decaying particle. A related consequence is that the decay of the field with the smallest coupling and hence the longest lifetime dominates the entropy and possibly the matter content of the Universe, a principle we refer to as “Maximum Baroqueness”. We also demonstrate that the dark sector should be colder than the ordinary sector, relaxing the most stringent free-streaming constraints on light darkmatter candidates. We will discuss the potential implications for the core-cusp problem in a follow-up paper. The FDM framework will furthermore have interesting baryogenesis implications. One possibility is that darkmatter is like the baryon asymmetry and both are simultaneously diluted by a late entropy dump. Alternatively, FDM is compatible with an elegant

What is the darkmatter that fills the Universe and binds together galaxies? How was it produced? What are its interactions and particle properties?The paradigm of darkmatter is one of the key developments at the interface of cosmology and elementary particle physics. It is also one of the foundations of the standard cosmological model. This book presents the state of the art in building and testing particle models for darkmatter. Each chapter gives an analysis of questions, research directions, and methods within the field. More than 200 problems are included to challenge and stimulate the reader's knowledge and provide guidance in the practical implementation of the numerous 'tools of the trade' presented. Appendices summarize the basics of cosmology and particle physics needed for any quantitative understanding of particle models for darkmatter.This interdisciplinary textbook is essential reading for anyone interested in the microscopic nature of darkmatter as it manifests itself in particle physics ex...

Full Text Available We study the possibility of generating tiny neutrino mass through a combination of type I and type II seesaw mechanism within the framework of an abelian extension of standard model. The model also provides a naturally stable darkmatter candidate in terms of the lightest neutral component of a scalar doublet. We compute the relic abundance of such a darkmatter candidate and also point out how the strength of type II seesaw term can affect the relic abundance of darkmatter. Such a model which connects neutrino mass and darkmatter abundance has the potential of being verified or ruled out in the ongoing neutrino, darkmatter, as well as accelerator experiments.

The nature of darkmatter is unknown. A number of darkmatter candidates are quantum flavor-mixed particles but this property has never been accounted for in cosmology. Here we explore this possibility from the first principles via extensive N-body cosmological simulations and demonstrate that the two-component darkmatter model agrees with observational data at all scales. Substantial reduction of substructure and flattening of density profiles in the centers of darkmatter halos found in simulations can simultaneously resolve several outstanding puzzles of modern cosmology. The model shares the "why now?" fine-tuning caveat pertinent to all self-interacting models. Predictions for direct and indirect detection darkmatter experiments are made.

We consider scenarios in which the annihilation of self-conjugate spin-1 darkmatter to a Standard Model fermion–antifermion final state is chirality suppressed, but where this suppression can be lifted by the emission of an additional photon via internal bremsstrahlung. We find that this scenario can only arise if the initial darkmatter state is polarized, which can occur in the context of self-interacting darkmatter. In particular, this is possible if the darkmatter pair forms a bound state that decays to its ground state before the constituents annihilate. We show that the shape of the resulting photon spectrum is the same as for self-conjugate spin-0 and spin-1/2 darkmatter, but the normalization is less heavily suppressed in the limit of heavy mediators.

Darkmatter could have an electroweak origin, yet communicate with the visible sector exclusively through gravitational interactions. In a set-up addressing the hierarchy problem, we propose a new darkmatter scenario where gravitational mediators, arising from the compactification of extra-dimensions, are responsible for darkmatter interactions and its relic abundance in the Universe. We write an explicit example of this mechanism in warped extra-dimensions and work out its constraints. We also develop a dual picture of the model, based on a four-dimensional scenario with partial compositeness. We show that Gravity-mediated DarkMatter is equivalent to a mechanism of generating viable darkmatter scenarios in a strongly-coupled, near-conformal theory, such as in composite Higgs models.

Guided by gauge principles we discuss a predictive and falsifiable UV complete model where the Dirac fermion that accounts for the cold darkmatter abundance in our Universe induces the lepton flavor violation (LFV) decays μ →e γ and μ →e e e as well as μ -e conversion. We explore the interplay between direct darkmatter detection, relic density, collider probes and lepton flavor violation to conclusively show that one may have a viable darkmatter candidate yielding flavor violation signatures that can be probed in the upcoming experiments. In fact, keeping the darkmatter mass at the TeV scale, a sizable LFV signal is possible, while reproducing the correct darkmatter relic density and meeting limits from direct-detection experiments.

We study the effects of cold darkmatter on the propagation of gravitational waves of astrophysical and primordial origin. We show that the dominant effect of cold darkmatter on gravitational waves from astrophysical sources is a small frequency dependent modification of the propagation speed of gravitational waves. However, the magnitude of the effect is too small to be detected in the near future. We furthermore show that the spectrum of primordial gravitational waves in principle contains detailed information about the properties of darkmatter. However, depending on the wavelength, the effects are either suppressed because the darkmatter is highly nonrelativistic or because it contributes a small fraction of the energy density of the universe. As a consequence, the effects of cold darkmatter on primordial gravitational waves in practice also appear too small to be detectable.

Physical process version of the first law of black hole thermodynamics in Einstein-Maxwell darkmatter gravity was derived. The darkmatter sector is mimicked by the additional U(1)-gauge field coupled to the ordinary Maxwell one. By considering any cross section of the black hole event horizon to the future of the bifurcation surface, the equilibrium state version of the first law of black hole mechanics was achieved. The considerations were generalized to the case of Einstein-Yang-Mills darkmatter gravity theory. The main conclusion is that the influence of darkmatter is crucial in the formation process of black objects. This fact may constitute the explanation of the recent observations of the enormous mass of the super luminous quasars formed in a relatively short time after Big Bang. We also pay attention to the compact binaries thermodynamics, when darkmatter sector enters the game.

Within the framework of the Minimal Supersymmetric Standard Model (MSSM), we explore a decoupling of the parameters into separate sectors that determine consistency with collider data, the abundance of darkmatter, and potential signatures at direct darkmatter searches. We consider weak-scale bino-like neutralino darkmatter, and find that annihilations via light slepton exchange present a viable mechanism for obtaining the appropriate darkmatter abundance assuming a thermal history. Constraints and prospects for discovery of these models are discussed, including the possibility that direct darkmatter searches may be sensitive to these models if light squarks exhibit left-right mixing. Differences between the scenarios presented here and the typical expectations for the MSSM are discussed.

Full Text Available We review matter bounce scenarios where the matter content is darkmatter and dark energy. These cosmologies predict a nearly scale-invariant power spectrum with a slightly red tilt for scalar perturbations and a small tensor-to-scalar ratio. Importantly, these models predict a positive running of the scalar index, contrary to the predictions of the simplest inflationary and ekpyrotic models, and hence, could potentially be falsified by future observations. We also review how bouncing cosmological space-times can arise in theories where either the Einstein equations are modified or where matter fields that violate the null energy condition are included.

We investigate the physics of darkmatter models featuring composite bound states carrying a large conserved dark “nucleon” number. The properties of sufficiently large dark nuclei may obey simple scaling laws, and we find that this scaling can determine the number distribution of nuclei resulting from Big Bang Dark Nucleosynthesis. For plausible models of asymmetric darkmatter, dark nuclei of large nucleon number, e.g. ≳10 8 , may be synthesised, with the number distribution taking one of two characteristic forms. If small-nucleon-number fusions are sufficiently fast, the distribution of dark nuclei takes on a logarithmically-peaked, universal form, independent of many details of the initial conditions and small-number interactions. In the case of a substantial bottleneck to nucleosynthesis for small dark nuclei, we find the surprising result that even larger nuclei, with size ≫10 8 , are often finally synthesised, again with a simple number distribution. We briefly discuss the constraints arising from the novel dark sector energetics, and the extended set of (often parametrically light) dark sector states that can occur in complete models of nuclear darkmatter. The physics of the coherent enhancement of direct detection signals, the nature of the accompanying dark-sector form factors, and the possible modifications to astrophysical processes are discussed in detail in a companion paper.

Recently there has been much interest in hidden sectors, especially in the context of darkmatter and ''dark forces'', since they are a common feature of beyond standard model scenarios like string theory and SUSY and additionally exhibit interesting phenomenological aspects. Various laboratory experiments place limits on the so-called hidden photon and continuously further probe and constrain the parameter space; an updated overview is presented here. Furthermore, for several hidden sector models with light darkmatter we study the viability with respect to the relic abundance and direct detection experiments.

Extra dimensions can be very useful tools when constructing new physics models. Previously, we began investigating toy models for the 5-D analog of the kinetic mixing/vector portal scenario where the interactions of bulk darkmatter with the brane-localized fields of the Standard Model are mediated by a massive $U(1)_D$ dark photon also living in the bulk. In that setup, where the darkmatter was taken to be a complex scalar, a number of nice features were obtained such as $U(1)_D$ breaking b...

The last several years have included remarkable advances in two of the primary areas of fundamental particle physics: the search for darkmatter and the discovery of the Higgs boson. This dissertation will highlight some contributions made on the forefront of these exciting fields. Although the circumstantial evidence supporting the darkmatter hypothesis is now almost undeniably significant, indisputable direct proof is still lacking. As the direct searches for darkmatter continue, we can maximize our prospects of discovery by using theoretical techniques complementary to the observational searches to rule out additional, otherwise accessible parameter space. In this dissertation, I report bounds on a wide range of darkmatter theories. The models considered here cover the spectrum from the canonical case of self-conjugate darkmatter with weak-scale interactions, to electrically charged darkmatter, to non-annihilating, non-fermionic darkmatter. These bounds are obtained from considerations of astrophysical and cosmological data, including, respectively: diffuse gamma ray photon observations; structure formation considerations, along with an explication of the novel local darkmatter structure due to galactic astrophysics; and the existence of old pulsars in dark-matter-rich environments. I also consider the prospects for a model of neutrino darkmatter which has been motivated by a wide set of seemingly contradictory experimental results. In addition, I include a study that provides the tools to begin solving the speculative ``inverse'' problem of extracting darkmatter properties solely from hypothetical nuclear energy spectra, which we may face if darkmatter is discovered with multiple direct detection experiments. In contrast to the null searches for darkmatter, we have the example of the recent discovery of the Higgs boson. The Higgs boson is the first fundamental scalar particle ever observed, and precision measurements of the production and

The darkmatter of our galactic halo may be constituted by elementary particles that interact weakly with with ordinary matter (WIMPs). In spite of the very low counting rates expected for these darkmatter particle to scatter off nuclei in a laboratory detector, such direct WIMP searches are possible and are experimentally carried out at present. An introduction to the theoretical ingredients entering the counting rates predictions, together with a short discussion of the major theoretical uncertainties, is here presented. (author)

We propose a model based on radiative symmetry breaking that combines inflation with dark energy and is consistent with the Wilkinson Microwave Anisotropy Probe 7-year regions. The radiative inflationary potential leads to the prediction of a spectral index 0.955 S < or approx. 0.967 and a tensor to scalar ratio 0.142 < or approx. r < or approx. 0.186, both consistent with current data but testable by the Planck experiment. The radiative symmetry breaking close to the Planck scale gives rise to a pseudo Nambu-Goldstone boson with a gravitationally suppressed mass which can naturally play the role of a quintessence field responsible for dark energy. Finally, we present a possible extra dimensional scenario in which our model could be realized.

The idea that darkmatter forms part of a larger dark sector is very intriguing, given the high degree of complexity of the visible sector. In this paper, we discuss lepton jets as a promising signature of an extended dark sector. As a simple toy model, we consider an O(GeV) DM fermion coupled to a new U(1) ′ gauge boson (dark photon) with a mass of order GeV and kinetically mixed with the Standard Model photon. Darkmatter production at the LHC in this model is typically accompanied by collinear radiation of dark photons whose decay products can form lepton jets. We analyze the dynamics of collinear dark photon emission both analytically and numerically. In particular, we derive the dark photon energy spectrum using recursive analytic expressions, using Monte Carlo simulations in Pythia, and using an inverse Mellin transform to obtain the spectrum from its moments. In the second part of the paper, we simulate the expected lepton jet signatures from radiating darkmatter at the LHC, carefully taking into account the various dark photon decay modes and allowing for both prompt and displaced decays. Using these simulations, we recast two existing ATLAS lepton jet searches to significantly restrict the parameter space of extended dark sector models, and we compute the expected sensitivity of future LHC searches.

We propose a simplified model of darkmatter with a scalar mediator to accommodate the di-photon excess recently observed by the ATLAS and CMS collaborations. Decays of the resonance into darkmatter can easily account for a relatively large width of the scalar resonance, while the magnitude of the total width combined with the constraint on darkmatter relic density leads to sharp predictions on the parameters of the Dark Sector. Under the assumption of a rather large width, the model predicts a signal consistent with ∼300 GeV darkmatter particle and ∼750 GeV scalar mediator in channels with large missing energy. This prediction is not yet severely bounded by LHC Run I searches and will be accessible at the LHC Run II in the jet plus missing energy channel with more luminosity. Our analysis also considers astro-physical constraints, pointing out that future direct detection experiments will be sensitive to this scenario.

We propose a simplified model of darkmatter with a scalar mediator to accommodate the di-photon excess recently observed by the ATLAS and CMS collaborations. Decays of the resonance into darkmatter can easily account for a relatively large width of the scalar resonance, while the magnitude of the total width combined with the constraint on darkmatter relic density leads to sharp predictions on the parameters of the Dark Sector. Under the assumption of a rather large width, the model predicts a signal consistent with ∼300 GeV darkmatter particle and ∼750 GeV scalar mediator in channels with large missing energy. This prediction is not yet severely bounded by LHC Run I searches and will be accessible at the LHC Run II in the jet plus missing energy channel with more luminosity. Our analysis also considers astro-physical constraints, pointing out that future direct detection experiments will be sensitive to this scenario.

. In this case the WIMP miracle is a mirage, and instead minimality as dictated by Occam's razor would indicate that darkmatter is related to the Planck scale, where quantum gravity is anyway expected to manifest itself. Assuming within this framework that darkmatter is a Planckian Interacting Massive Particle......, we show that the most natural mass larger than $0.01\\,\\textrm{M}_p$ is already ruled out by the absence of tensor modes in the CMB. This also indicates that we expect tensor modes in the CMB to be observed soon for this type of minimal darkmatter model. Finally, we touch upon the KK graviton mode...... as a possible realization of this scenario within UV complete models, as well as further potential signatures and peculiar properties of this type of darkmatter candidate. This paradigm therefore leads to a subtle connection between quantum gravity, the physics of primordial inflation, and the nature of dark...

While there is tremendous astrophysical and cosmological evidence for darkmatter, its precise nature is one of the most significant open questions in modern physics. Weakly interacting massive particles (WIMPs) are a particularly compelling class of darkmatter candidates with masses of the order 100 GeV and couplings to ordinary matter at the weak scale. Direct detection experiments are aiming to observe the low energy (<100 keV) scattering of darkmatter off normal matter. With the liquid noble technology leading the way in WIMP sensitivity, no conclusive signals have been observed yet. The DarkSide experiment is looking for WIMP darkmatter using a liquid argon target in a dual-phase time projection chamber located deep underground at Gran Sasso National Laboratory (LNGS) in Italy. Currently filled with argon obtained from underground sources, which is greatly reduced in radioactive 39Ar, DarkSide-50 recently made the most sensitive measurement of the 39Ar activity in underground argon and used it to set the strongest WIMP darkmatter limit using liquid argon to date. This work describes the full chain of analysis used to produce the recent darkmatter limit, from reconstruction of raw data to evaluation of the final exclusion curve. The DarkSide- 50 apparatus is described in detail, followed by discussion of the low level reconstruction algorithms. The algorithms are then used to arrive at three broad analysis results: The electroluminescence signals in DarkSide-50 are used to perform a precision measurement of ii longitudinal electron diffusion in liquid argon. A search is performed on the underground argon data to identify the delayed coincidence signature of 85Kr decays to the 85mRb state, a crucial ingredient in the measurement of the 39Ar activity in the underground argon. Finally, a full description of the WIMP search is given, including development of cuts, efficiencies, energy scale, and exclusion

Full Text Available We propose a novel coupled dark energy model which is assumed to occur as a q-deformed scalar field and investigate whether it will provide an expanding universe phase. We consider the q-deformed dark energy as coupled to darkmatter inhomogeneities. We perform the phase-space analysis of the model by numerical methods and find the late-time accelerated attractor solutions. The attractor solutions imply that the coupled q-deformed dark energy model is consistent with the conventional dark energy models satisfying an acceleration phase of universe. At the end, we compare the cosmological parameters of deformed and standard dark energy models and interpret the implications.

Mysterious darkmatter constitutes about 85 per cent of all masses in the Universe. Clustering of darkmatter plays a dominant role in the formation of all observed structures on scales from a fraction to a few hundreds of Mega-parsecs. Galaxies play a role of lights illuminating these structures so they can be observed. The observations in the last several decades have unveiled opulent geometry of these structures currently known as the cosmic web. Haloes are the highest concentrations of darkmatter and host luminous galaxies. Currently the most accurate modelling of darkmatter haloes is achieved in cosmological N-body simulations. Identifying the haloes from the distribution of particles in N-body simulations is one of the problems attracting both considerable interest and efforts. We propose a novel framework for detecting potential darkmatter haloes using the field unique for darkmatter-multistream field. The multistream field emerges at the non-linear stage of the growth of perturbations because the darkmatter is collisionless. Counting the number of velocity streams in gravitational collapses supplements our knowledge of spatial clustering. We assume that the virialized haloes have convex boundaries. Closed and convex regions of the multistream field are hence isolated by imposing a positivity condition on all three eigenvalues of the Hessian estimated on the smoothed multistream field. In a single-scale analysis of high multistream field resolution and low softening length, the halo substructures with local multistream maxima are isolated as individual halo sites.

This chapter presents the elaborated lecture notes on Multi-Messenger Astronomy and DarkMatter given by Lars Bergström at the 40th Saas-Fee Advanced Course on "Astrophysics at Very High Energies". One of the main problems of astrophysics and astro-particle physics is that the nature of darkmatter remains unsolved. There are basically three complementary approaches to try to solve this problem. One is the detection of new particles with accelerators, the second is the observation of various types of messengers from radio waves to gamma-ray photons and neutrinos, and the third is the use of ingenious experiments for direct detection of darkmatter particles. After giving an introduction to the particle universe, the author discusses the relic density of particles, basic cross sections for neutrinos and gamma-rays, supersymmetric darkmatter, detection methods for neutralino darkmatter, particular darkmatter candidates, the status of darkmatter detection, a detailled calculation on an hypothetical "Saas-Fee Wimp", primordial black holes, and gravitational waves.

We consider the steady-state regime describing the density profile of a darkmatter halo, if darkmatter is treated as a Bose-Einstein condensate. We first solve the fluid equation for “canonical” cold darkmatter, obtaining a class of density profiles which includes the Navarro-Frenk-White profile, and which diverge at the halo core. We then solve numerically the equation obtained when an additional “quantum pressure” term is included in the computation of the density profile. The solution to this latter case is finite at the halo core, possibly avoiding the “cuspy halo problem” present in some cold darkmatter theories. Within the model proposed, we predict the mass of the cold darkmatter particle to be of the order of M_χc"2≈10"−"2"4 eV, which is of the same order of magnitude as that predicted in ultra-light scalar cold darkmatter models. Finally, we derive the differential equation describing perturbations in the density and the pressure of the darkmatter fluid.

Processes with darkmatter interacting with the standard model fermions through new scalars or pseudoscalars with flavor-diagonal couplings proportional to fermion mass are well motivated theoretically, and provide a useful phenomenological model with which to interpret experimental results. Two modes of darkmatter production from these models have been considered in the existing literature: pairs of darkmatter produced through top quark loops with an associated monojet in the event, and pair production of darkmatter with pairs of heavy flavored quarks (tops or bottoms). In this paper, we demonstrate that a third, previously overlooked channel yields a non-negligible contribution to LHC darkmatter searches in these models. In spite of a generally lower production cross section at LHC when compared to the associated top-pair channel, non-flavor violating single top quark processes are kinematically favored and can significantly increase the sensitivity to these models. Including darkmatter production in association with a single top quark through scalar or pseudoscalar mediators, the exclusion limit set by the LHC searches for darkmatter can be improved by 30% up to a factor of two, depending on the mass assumed for the mediator particle.

How do observed voids relate to the underlying darkmatter distribution? To examine the spatial distribution of darkmatter contained within voids identified in galaxy surveys, we apply Halo Occupation Distribution models representing sparsely and densely sampled galaxy surveys to a high-resolution N-body simulation. We compare these galaxy voids to voids found in the halo distribution, low-resolution darkmatter and high-resolution darkmatter. We find that voids at all scales in densely sampled surveys - and medium- to large-scale voids in sparse surveys - trace the same underdensities as darkmatter, but they are larger in radius by ˜20 per cent, they have somewhat shallower density profiles and they have centres offset by ˜ 0.4Rv rms. However, in void-to-void comparison we find that shape estimators are less robust to sampling, and the largest voids in sparsely sampled surveys suffer fragmentation at their edges. We find that voids in galaxy surveys always correspond to underdensities in the darkmatter, though the centres may be offset. When this offset is taken into account, we recover almost identical radial density profiles between galaxies and darkmatter. All mock catalogues used in this work are available at http://www.cosmicvoids.net.

It is well known that stable weak scale particles are viable darkmatter candidates since the annihilation cross section is naturally about the right magnitude to leave the correct thermal residual abundance. Many darkmatter searches have focused on relatively light darkmatter consistent with weak couplings to the Standard Model. However, in a strongly coupled theory, or even if the coupling is just a few times bigger than the Standard Model couplings, darkmatter can have TeV-scale mass with the correct thermal relic abundance. Here we consider neutral TeV-mass scalar darkmatter, its necessary interactions, and potential signals. We consider signals both with and without higher-dimension operators generated by strong coupling at the TeV scale, as might happen for example in an RS scenario. We find some potential for detection in high energy photons that depends on the darkmatter distribution. Detection in positrons at lower energies, such as those PAMELA probes, would be difficult though a higher energy positron signal could in principle be detectable over background. However, a light darkmatter particle with higher-dimensional interactions consistent with a TeV cutoff can in principle match PAMELA data.

The darkmatter content of the universe is likely to be a mixture of matter and antimatter, perhaps comparable to the measured asymmetric mixture of baryons and antibaryons. During the early stages of the universe, the darkmatter particles are produced in a process similar to baryogenesis, and darkmatter freezeout depends on the darkmatter asymmetry and the annihilation cross section (s-wave and p-wave annihilation channels) of particles and antiparticles. In these {eta}-parameterized asymmetric darkmatter ({eta}ADM) models, the darkmatter particles have an annihilation cross section close to the weak interaction cross section, and a value of darkmatter asymmetry {eta} close to the baryon asymmetry {eta}{sub B}. Furthermore, we assume that darkmatter scattering of baryons, namely, the spin-independent scattering cross section, is of the same order as the range of values suggested by several theoretical particle physics models used to explain the current unexplained events reported in the DAMA/LIBRA, CoGeNT, and CRESST experiments. Here, we constrain {eta}ADM by investigating the impact of such a type of darkmatter on the evolution of the Sun, namely, the flux of solar neutrinos and helioseismology. We find that darkmatter particles with a mass smaller than 15 GeV, a spin-independent scattering cross section on baryons of the order of a picobarn, and an {eta}-asymmetry with a value in the interval 10{sup -12}-10{sup -10}, would induce a change in solar neutrino fluxes in disagreement with current neutrino flux measurements. This result is also confirmed by helioseismology data. A natural consequence of this model is suppressed annihilation, thereby reducing the tension between indirect and direct darkmatter detection experiments, but the model also allows a greatly enhanced annihilation cross section. All the cosmological {eta}ADM scenarios that we discuss have a relic darkmatter density {Omega}h {sup 2} and baryon asymmetry {eta}{sub B} in agreement with

The darkmatter content of the universe is likely to be a mixture of matter and antimatter, perhaps comparable to the measured asymmetric mixture of baryons and antibaryons. During the early stages of the universe, the darkmatter particles are produced in a process similar to baryogenesis, and darkmatter freezeout depends on the darkmatter asymmetry and the annihilation cross section (s-wave and p-wave annihilation channels) of particles and antiparticles. In these η-parameterized asymmetric darkmatter (ηADM) models, the darkmatter particles have an annihilation cross section close to the weak interaction cross section, and a value of darkmatter asymmetry η close to the baryon asymmetry η B . Furthermore, we assume that darkmatter scattering of baryons, namely, the spin-independent scattering cross section, is of the same order as the range of values suggested by several theoretical particle physics models used to explain the current unexplained events reported in the DAMA/LIBRA, CoGeNT, and CRESST experiments. Here, we constrain ηADM by investigating the impact of such a type of darkmatter on the evolution of the Sun, namely, the flux of solar neutrinos and helioseismology. We find that darkmatter particles with a mass smaller than 15 GeV, a spin-independent scattering cross section on baryons of the order of a picobarn, and an η-asymmetry with a value in the interval 10 –12 -10 –10 , would induce a change in solar neutrino fluxes in disagreement with current neutrino flux measurements. This result is also confirmed by helioseismology data. A natural consequence of this model is suppressed annihilation, thereby reducing the tension between indirect and direct darkmatter detection experiments, but the model also allows a greatly enhanced annihilation cross section. All the cosmological ηADM scenarios that we discuss have a relic darkmatter density Ωh 2 and baryon asymmetry η B in agreement with the current WMAP measured values, Ω DM h 2 = 0

We discuss how to formulate a quantum field theory of dark energy interacting with darkmatter. We show that the proposals based on the assumption that darkmatter is made up of heavy particles with masses which are very sensitive to the value of dark energy are strongly constrained. Quintessence-generated long range forces and radiative stability of the quintessence potential require that such darkmatter and dark energy are completely decoupled. However, if dark energy and a fraction of darkmatter are very light axions, they can have significant mixings which are radiatively stable and perfectly consistent with quantum field theory. Such models can naturally occur in multi-axion realizations of monodromies. The mixings yield interesting signatures which are observable and are within current cosmological limits but could be constrained further by future observations.

There is good evidence from N-body simulations that the velocity distribution in the outer parts of halos is radially anisotropic, with the kinetic energy in the radial direction roughly equal to the sum of that in the two tangential directions. We provide a simple algorithm to generate such cosmologically important distribution functions. Introducing r E (E), the radius of the largest orbit of a particle with energy E, we show how to write down almost trivially a distribution function of the form f(E,L)=L -1 g(r E ) for any spherical model - including the 'universal' halo density law (Navarro-Frenk-White profile). We in addition give the generic form of the distribution function for any model with a local density power-law index α and anisotropy parameter β and provide limiting forms appropriate for the central parts and envelopes of darkmatter halos. From those, we argue that, regardless of the anisotropy, the density falloff at large radii must evolve to ρ∼r -4 or steeper ultimately

There exists a vast literature examining the electroweak (EW) fine-tuning problem in supersymmetric scenarios, but little concerned with the darkmatter (DM) one, which should be combined with the former. In this paper, we study this problem in an, as much as possible, exhaustive and rigorous way. We have considered the MSSM framework, assuming that the LSP is the lightest neutralino, χ{sub 1}{sup 0}, and exploring the various possibilities for the mass and composition of χ{sub 1}{sup 0}, as well as different mechanisms for annihilation of the DM particles in the early Universe (well-tempered neutralinos, funnels and co-annihilation scenarios). We also present a discussion about the statistical meaning of the fine-tuning and how it should be computed for the DM abundance, and combined with the EW fine-tuning. The results are very robust and model-independent and favour some scenarios (like the h-funnel when M{sub χ{sub 1{sup 0}}} is not too close to m{sub h}/2) with respect to others (such as the pure wino case). These features should be taken into account when one explores “natural SUSY” scenarios and their possible signatures at the LHC and in DM detection experiments.

Cosmologists responded enthusiastically to the announcement at the Washington meeting of the American Physical Society in April 1992 that the Cosmic Background Explorer (COBE) had succeeded in detecting primordial anisotropies in the cosmic microwave background radiation (CMB - June 1992, page 1). The COBE satellite was launched in November 1989 into an orbit approximately 900 km above the Earth, carrying instruments to make precise measurements of the spectrum and anisotropy of the CMB. Data from the Far-lnfra Red Absolute Spectrophotometer (FIRAS) beautifully shows the CMB spectrum to be that of a black body at a temperature of 2.73±0.06K. An even more important result, at least from the viewpoint of theories of large scale structure formation (LSS), comes from the Differential Microwave Radiometer (DMR) which provided the first evidence for CMB anisotropy. Some anisotropy on the angular slice probed by COBE is expected in any reasonable model of LSS. COBE's measurement of the quadrupole anisotropy at six parts per million provides an important clue for developing a 'standard model' of LSS. The COBE numbers are in remarkably good agreement with the predictions of a particularly simple class of LSS models proposed almost a decade ago, with far reaching implications for darkmatter searches

Determining the precise nature of darkmatter is one of the main open questions of contemporary physics. The search for non-baryonic darkmatter is strongly motivated by present data and 3 particle candidates: wimps (weakly interactive massive particles), axions and massive neutrinos are actively searched by several experiments (GENIUS, HDMS, CDMS, EDELWEISS, LLNL, CARRACK, SOLAX, DAMA,...). In this course the author reviews and summarizes the experimental situation and analyzes the main detection strategies developed to identify the darkmatter candidates. (A.C.)

The ordinary atoms that make up the known universe-from our bodies and the air we breathe to the planets and stars-constitute only 5 percent of all matter and energy in the cosmos. The rest is known as darkmatter and dark energy, because their precise identities are unknown. The Cosmic Cocktail is the inside story of the epic quest to solve one of the most compelling enigmas of modern science - what is the universe made of? - told by one of today's foremost pioneers in the study of darkmatter. Blending cutting-edge science with her own behind-the-scenes insights as a leading researcher in the

Light extra U(1) gauge bosons, so called hidden photons, which reside in a hidden sector have attracted much attention since they are a well motivated feature of many scenarios beyond the Standard Model and furthermore could mediate the interaction with hidden sector darkmatter.We review limits on hidden photons from past electron beam dump experiments including two new limits from such experiments at KEK and Orsay. In addition, we study the possibility of having darkmatter in the hidden sector. A simple toy model and different supersymmetric realisations are shown to provide viable darkmatter candidates in the hidden sector that are in agreement with recent direct detection limits.

The presence of a non-baryonic darkmatter component in the Universe is inferred from the observation of its gravitational interaction. If darkmatter interacts weakly with the Standard Model it would be produced at the LHC, escaping the detector and leaving a large missing transverse momentum as their signature. The ATLAS detector has developed a broad and systematic search program for darkmatter production in LHC collisions. The results of these searches on the first 13 TeV data, their interpretation, and the design and possible evolution of the search program will be presented.

The presence of a non-baryonic darkmatter component in the Universe is inferred from the observation of its gravitational interaction. If darkmatter interacts weakly with the Standard Model it would be produced at the LHC, escaping the detector and leaving a large missing transverse momentum as its signature. The ATLAS detector has developed a broad and systematic search program for darkmatter production in LHC collisions. The results of these searches on the first 13 TeV data, their interpretation, and the design and possible evolution of the search program will be presented.

High resolution cosmological N-body simulations of four galaxy-scale darkmatter halos are compared to corresponding N-body/hydrodynamical simulations containing darkmatter, stars and gas. The simulations without baryons share features with others described in the literature in that the darkmatter density slope continuously decreases towards the center, with a density ρ DM ∝r -1.3±0.2 , at about 1% of the virial radius for our Milky Way sized galaxies. The central cusps in the simulations which also contain baryons steepen significantly, to ρ DM ∝r -1.9±0.2 , with an indication of the inner logarithmic slope converging. Models of adiabatic contraction of darkmatter halos due to the central buildup of stellar/gaseous galaxies are examined. The simplest and most commonly used model, by Blumenthal et al., is shown to overestimate the central darkmatter density considerably. A modified model proposed by Gnedin et al. is tested and it is shown that, while it is a considerable improvement, it is not perfect. Moreover, it is found that the contraction parameters in their model not only depend on the orbital structure of the dark-matter-only halos but also on the stellar feedback prescription which is most relevant for the baryonic distribution. Implications for darkmatter annihilation at the galactic center are discussed and it is found that, although our simulations show a considerable reduced darkmatter halo contraction as compared to the Blumenthal et al. model, the fluxes from darkmatter annihilation are still expected to be enhanced by at least a factor of a hundred, as compared to dark-matter-only halos. Finally, it is shown that, while dark-matter-only halos are typically prolate, the darkmatter halos containing baryons are mildly oblate with minor-to-major axis ratios of c/a=0.73±0.11, with their flattening aligned with the central baryonic disks

The presence of a non-baryonic DarkMatter component in the Universe is inferred from the observation of its gravitational interaction. If DarkMatter interacts weakly with the Standard Model particles it may be produced at the Large Hadron Collider (LHC), escaping detection and leaving large missing transverse momentum as its signature. New results from the DarkMatter search programme of the ATLAS experiment are presented, based on LHC proton-proton collision data collected at a center-of-mass energy of 13 TeV.

The presence of a non-baryonic darkmatter component in the Universe is inferred from the observation of its gravitational interaction. If darkmatter interacts weakly with the Standard Model it would be produced at the LHC, escaping the detector and leaving a large missing transverse momentum as their signature. The ATLAS detector has developed a broad and systematic search program for darkmatter production in LHC collisions. The results of these searches on the first 13 TeV data, their interpretation, and the design and possible evolution of the search program will be presented.

The presence of a non-baryonic darkmatter component in the Universe is inferred from the observation of its gravitational interaction. If darkmatter interacts weakly with the Standard Model it would be produced at the LHC, escaping the detector and leaving a large missing transverse momentum as its signature. The ATLAS detector has developed a broad and systematic search program for darkmatter production in LHC collisions. The results of these searches using the first 13 TeV data, their interpretation, and the design and possible evolution of the search program will be presented.

Full Text Available The presence of a non-baryonic darkmatter component in the Universe is inferred from the observation of its gravitational interaction. If darkmatter interacts weakly with the Standard Model it would be produced at the LHC, escaping the detector and leaving a large missing transverse momentum as its signature. The ATLAS detector has developed a broad and systematic search program for darkmatter production in LHC collisions. The results of these searches on the first 13 TeV data, their interpretation, and the design and possible evolution of the search program will be presented.

We examine vortices in a self-gravitating darkmatter Bose-Einstein condensate (BEC), consisting of ultra-low mass scalar bosons that arise during a late-time cosmological phase transition. Rotation of the darkmatter BEC imprints a background phase gradient on the condensate, which establishes a harmonic trap potential for vortices. A numerical simulation of vortex dynamics shows that the vortex number density, n v ∝ r -1 , resulting in a flat velocity profile for the darkmatter condensate. (letter to the editor)

Although the existence of DarkMatter (DM) is well established by many astronomical measurements, its nature still remains one of the unsolved puzzles of particles physics. The unprecedented energy reached by the Large Hadron Collider (LHC) at CERN has allowed exploration of previously unaccessible kinematic regimes in the search for new phenomena. An overview of most recent searches for darkmatter with the ATLAS detector at LHC is presented and the interpretation of the results in terms of effective field theory and simplified models is discussed. The exclusion limits set by the ATLAS searches are compared to the constraints from direct darkmatter detection experiments.

Light extra U(1) gauge bosons, so called hidden photons, which reside in a hidden sector have attracted much attention since they are a well motivated feature of many scenarios beyond the Standard Model and furthermore could mediate the interaction with hidden sector darkmatter.We review limits on hidden photons from past electron beam dump experiments including two new limits from such experiments at KEK and Orsay. In addition, we study the possibility of having darkmatter in the hidden sector. A simple toy model and different supersymmetric realisations are shown to provide viable darkmatter candidates in the hidden sector that are in agreement with recent direct detection limits.

We present general constraints on darkmatter stability in hadronic decay channels derived from measurements of cosmic-ray antiprotons.We analyze various hadronic decay modes in a model-independent manner by examining the lowest-order decays allowed by gauge and Lorentz invariance for scalar and fermionic darkmatter particles and present the corresponding lower bounds on the partial decay lifetimes in those channels. We also investigate the complementarity between hadronic and gamma-ray constraints derived from searches for monochromatic lines in the sky, which can be produced at the quantum level if the darkmatter decays into quark-antiquark pairs at leading order.

Many forms of experimental evidence point to the existence of DarkMatter within the universe. As of yet, however, it's particle nature has not been discovered. Presented will be an overview of run-2 searches for DarkMatter at the ATLAS detector. The focus of the these studies are based on simplified signal models, moving away from the EFT based approach during run-1. An overview of such searches will be given, along with recent results and discussion as to the future of DarkMatter searches at ATLAS.

We derive new bounds on decaying darkmatter from the gamma ray measurements of (i) the isotropic residual (extragalactic) background by Fermi and (ii) the Fornax galaxy cluster by H.E.S.S. We find that those from (i) are among the most stringent constraints currently available, for a large range...... of darkmatter masses and a variety of decay modes, excluding half-lives up to similar to 10(26) to few 10(27) seconds. In particular, they rule out the interpretation in terms of decaying darkmatter of the e(+/-) spectral features in PAMELA, Fermi and H.E.S.S., unless very conservative choices...

We investigate darkmatter candidates emerging in recently proposed technicolor theories. We determine the relic density of the lightest, neutral, stable technibaryon having imposed weak thermal equilibrium conditions and overall electric neutrality of the Universe. In addition we consider...... sphaleron processes that violate baryon, lepton and technibaryon number. Our analysis is performed in the case of a first order electroweak phase transition as well as a second order one. We argue that, in both cases, the new technibaryon contributes to the darkmatter in the Universe. Finally we examine...... the problem of the constraints on these types of darkmatter components from earth based experiments....

We present general constraints on darkmatter stability in hadronic decay channels derived from measurements of cosmic-ray antiprotons.We analyze various hadronic decay modes in a model-independent manner by examining the lowest-order decays allowed by gauge and Lorentz invariance for scalar and fermionic darkmatter particles and present the corresponding lower bounds on the partial decay lifetimes in those channels. We also investigate the complementarity between hadronic and gamma-ray constraints derived from searches for monochromatic lines in the sky, which can be produced at the quantum level if the darkmatter decays into quark-antiquark pairs at leading order.

We consider a scenario, within the framework of the MSSM, in which darkmatter is bino-like and darkmatter-nucleon spin-independent scattering occurs via the exchange of light squarks which exhibit left-right mixing. We show that direct detection experiments such as LUX and SuperCDMS will be sensitive to a wide class of such models through spin-independent scattering. The dominant nuclear physics uncertainty is the quark content of the nucleon, particularly the strangeness content. We also investigate parameter space with nearly degenerate neutralino and squark masses, thus enhancing darkmatter annihilation and nucleon scattering event rates.

Darkmatter, one of the important portion of the universe, could affect the visible matter in neutron stars. An important physical feature of darkmatter is due to the spin of darkmatter particles. Here, applying the piecewise polytropic equation of state for the neutron star matter and the equation of state of spin polarized self-interacting darkmatter, we investigate the structure of neutron stars which are influenced by the spin polarized self-interacting darkmatter. The behavior of the...

We suggest that two-to-two darkmatter fusion may be the relaxation process that resolves the small-scale structure problems of the cold collisionless darkmatter paradigm. In order for the fusion cross section to scale correctly across many decades of astrophysical masses from dwarf galaxies to galaxy clusters, we require the fractional binding energy released to be greater than v^n ~ [10^{-(2-3)}]^n, where n=1,2 depends on local dark sector chemistry. The size of the dark-sector interaction cross sections must be sigma ~ 0.1-1 barn, moderately larger than for Standard Model deuteron fusion, indicating a dark nuclear scale Lambda ~ O(100 MeV). Dark fusion firmly predicts constant sigma v below the characteristic velocities of galaxy clusters. Observations of the inner structure of galaxy groups with velocity dispersion of several hundred kilometer per second, of which a handful have been identified, could differentiate dark fusion from a dark photon model.

The axion is a hypothetical elementary particle appearing in a simple and elegant extension to the Standard Model of particle physics that cancels otherwise huge CP-violating effects in QCD; this extension has a broken U(1) axial symmetry, where the resulting Goldstone Boson is the axion. A light axion of mass 10 -(6-3) eV (the so-called i nvisible axion ) would couple extraordinarily weakly to normal matter and radiation and would therefore be extremely difficult to detect in the laboratory. However, such an axion would be a compelling dark-matter candidate and is therefore a target of a number of searches. Compared to other dark-matter candidates, the plausible range of axion dark-matter couplings and masses is narrowly constrained. This restricted search space allows for 'definitive' searches, where non-observation would seriously impugn the dark-matter QCD-axion hypothesis. Axion searches employ a wide range of technologies and techniques, from astrophysical observations to laboratory electromagnetic signal detection. For some experiments, sensitivities are have reached likely dark-matter axion couplings and masses. This is a brief and selective overview of axion searches. With only very limited space, I briefly describe just two of the many experiments that are searching for dark-matter axions.

It has been argued that the observed core density profile of galaxies is inconsistent with having a darkmatter particle that is collisionless and that alternative darkmatter candidates which are self-interacting may explain observations better. One new class of self-interacting darkmatter that has been proposed in the context of mirror universe models of particle physics is the mirror hydrogen atom, whose stability is guaranteed by the conservation of mirror baryon number. We show that the effective transport cross section for mirror hydrogen atoms has the right order of magnitude for solving the 'cuspy' halo problem. Furthermore, the suppression of dissipation effects for mirror atoms due to a higher mirror mass scale prevents the mirror halo matter from collapsing into a disk, strengthening the argument for mirror matter as galactic darkmatter

Self-interacting darkmatter may have striking astrophysical signatures, such as observ- able offsets between galaxies and darkmatter in merging galaxy clusters. Numerical N-body simulations used to predict such observables typically treat the galaxies as collisionless test particles, a questionable assumption given that each galaxy is embedded in its own darkmatter halo. To enable a more accurate treatment we develop an effective description of small darkmatter haloes taking into account the two major effects due to darkmatter self-scatterings: deceleration and evaporation. We point out that self-scatterings can have a sizeable impact on the trajectories of galaxies, diminishing the separation between galaxies and darkmatter in merging clusters. This effect depends sensitively on the underlying particle physics, in particular the angular dependence of the self-scattering cross section, and cannot be predicted from the momentum transfer cross section alone.

In the late 20th century, cosmology became a precision science. Now, at the beginning of the next century, the parameters describing how our universe evolved from the Big Bang are generally known to a few percent. One key parameter is the total mass density of the universe. Normal matter constitutes only a small fraction of the total mass density. Observations suggest this additional mass, the darkmatter, is cold (that is, moving nonrelativistically in the early universe) and interacts feebly if at all with normal matter and radiation. There's no known such elementary particle, so the strong presumption is the darkmatter consists of particle relics of a new kind left over from the Big Bang. One of the most important questions in science is the nature of this darkmatter. One attractive particle dark-matter candidate is the axion. The axion is a hypothetical elementary particle arising in a simple and elegant extension to the standard model of particle physics that nulls otherwise observable CP-violating effects (where CP is the product of charge reversal C and parity inversion P) in quantum chromo dynamics (QCD). A light axion of mass 10(-(6-3)) eV (the invisible axion) would couple extraordinarily weakly to normal matter and radiation and would therefore be extremely difficult to detect in the laboratory. However, such an axion is a compelling dark-matter candidate and is therefore a target of a number of searches. Compared with other particle dark-matter candidates, the plausible range of axion dark-matter couplings and masses is narrowly constrained. This focused search range allows for definitive searches, where a nonobservation would seriously impugn the dark-matter QCD-axion hypothesis. Axion searches use a wide range of technologies, and the experiment sensitivities are now reaching likely dark-matter axion couplings and masses. This article is a selective overview of the current generation of sensitive axion searches. Not all techniques and experiments

A light hidden gauge boson with kinetic mixing with the usual photon is a popular setup in theories of darkmatter. The supernova cooling via radiating the hidden boson is known to put an important constraint on the mixing. I consider the possible role darkmatter, which under reasonable assumptions naturally exists inside supernova, can play in the cooling picture. Because the interaction between the hidden gauge boson and DM is likely unsuppressed, even a small number of darkmatter compared to protons inside the supernova could dramatically shorten the free streaming length of the hidden boson. A picture of a darkmatter “smog” inside the supernova, which substantially relaxes the cooling constraint, is discussed in detail

A light hidden gauge boson with kinetic mixing with the usual photon is a popular setup in theories of darkmatter. The supernova cooling via radiating the hidden boson is known to put an important constraint on the mixing. I consider the possible role darkmatter, which under reasonable assumptions naturally exists inside supernova, can play in the cooling picture. Because the interaction between the hidden gauge boson and DM is likely unsuppressed, even a small number of darkmatter compared to protons inside the supernova could dramatically shorten the free streaming length of the hidden boson. A picture of a darkmatter “smog” inside the supernova, which substantially relaxes the cooling constraint, is discussed in detail.

A light hidden gauge boson with kinetic mixing with the usual photon is a popular setup in theories of darkmatter. The supernova cooling via radiating the hidden boson is known to put an important constraint on the mixing. I consider the possible role darkmatter, which under reasonable assumptions naturally exists inside supernova, can play in the cooling picture. Because the interaction between the hidden gauge boson and DM is likely unsuppressed, even a small number of darkmatter compared to protons inside the supernova could dramatically shorten the free streaming length of the hidden boson. A picture of a darkmatter ''smog'' inside the supernova, which substantially relaxes the cooling constraint, is discussed in detail.

Under the hypothesis of a darkmatter composed by supersymmetric particles such as neutralinos, we investigate the possibility that their annihilation in the halos of nearby galaxies could produce detectable fluxes of γ photons. Expected fluxes depend on several, poorly known quantities such as the density profiles of darkmatter halos, the existence and prominence of central density cusps and the presence of a population of subhalos. We find that, for all reasonable choices of darkmatter halo models, the intensity of the γ-ray flux from some of the nearest extragalactic objects, such as M31, is comparable to or higher than the diffuse galactic foreground. We show that next generation ground-based experiments could have the sensitivity to reveal such fluxes which could help us to unveil the nature of darkmatter particles

The axion provides a solution to the strong CP problem and is a cold darkmatter candidate. I will review the limits on the axion from particle physics, stellar evolution and cosmology. The various constraints suggest that the axion mass is in the micro-eV to milli-eV range. In this range, axions contribute significantly to the energy density of the universe in the form of cold darkmatter. Darkmatter axions can be searched for on Earth by stimulating their conversion to microwave photons in an electromagnetic cavity permeated by a strong magnetic field. Using this technique, limits on the local halo density have been placed by the Axion DarkMatter experiment at Lawrence Livermore National Laboratory. I will give a status report on ADMX and its upgrade presently under construction. I will also discuss the results from solar axion searches (Tokyo helioscope, CAST) and laser experiments (PVLAS).

The scalar darkmatter candidate in a prototypical theory space little Higgs model is investigated. We review all details of the model pertinent to a relic density calculation. We perform a thermal relic density calculation including couplings to the gauge and Higgs sectors of the model. We find two regions of parameter space that give acceptable darkmatter abundances. The first region has a darkmatter candidate with a mass {Omicron}(100 GeV), the second region has a candidate with a mass greater than {Omicron}(500 GeV). The darkmatter candidate in either region is an admixture of an SU(2) triplet and an SU(2) singlet, thereby constituting a possible WIMP (weakly interacting massive particle).

DarkMatter composes almost 25% of our Universe, but its identity is still unknown which makes it a large challenge for current fundamental physics. A lot of approaches are used to discover the identity of DarkMatter and one of them, collider searches, are discussed in this talk. The latest results on DarkMatter search at ATLAS using 2015 and 2016 data are presented. Results from searches for new physics in the events with final states containing large missing transverse energy and a single photon or Higgs boson are shown. Higgs to invisible and dijet searches are used in sense of complementarity to constrain properties of DarkMatter. Results and perspectives for all these searches are presented.

.... The Earth may thus be regarded as a probe of the disc environment; and to account for the periodicity, the Galactic disc is required to have a substantial darkmatter component ( approx .15 molar mass/cu pc...

We discuss possible scale of $SU(4)$ darkmatter, in form of neutral baryons. We argue that it is very likely that those would have time to cluster into large "nuclear drops" in which they are Bose-condensed.

The scalar darkmatter candidate in a prototypical theory space little Higgs model is investigated. We review all details of the model pertinent to a relic density calculation. We perform a thermal relic density calculation including couplings to the gauge and Higgs sectors of the model. We find two regions of parameter space that give acceptable darkmatter abundances. The first region has a darkmatter candidate with a mass O(100 GeV), the second region has a candidate with a mass greater than O(500 GeV). The darkmatter candidate in either region is an admixture of an SU(2) triplet and an SU(2) singlet, thereby constituting a possible weakly interacting massive particle

This work presents a set of conventions and numerical structures that aim to provide a universal interface between computer programs calculating darkmatter related observables. It specifies input and output parameters for the calculation of observables such as abundance, direct and various indirect detection rates. These parameters range from cosmological to astrophysical to nuclear observables. The present conventions lay the foundations for defining a future Les Houches DarkMatter Accord. (authors)

This report is a brief review of the efforts to explain the nature of non-baryonic darkmatter and of the studies devoted to the search for relic particles. Among the different darkmatter candidates, special attention is devoted to relic neutralinos, by giving an overview of the recent calculations of its relic abundance and detection rates in a wide variety of supersymmetric schemes

This report is a brief review of the efforts to explain the nature of non-baryonic darkmatter and of the studies devoted to the search for relic particles. Among the different darkmatter candidates, special attention is devoted to relic neutralinos, by giving an overview of the recent calculations of its relic abundance and detection rates in a wide variety of supersymmetric schemes.

The epoch of the formation of the first stars, known as the cosmic dawn, has emerged as a new arena in the search for darkmatter. In particular, the first claimed 21-cm detection exhibits a deeper global absorption feature than expected, which could be caused by a low baryonic temperature. This has been interpreted as a sign for electromagnetic interactions between baryons and darkmatter. However, in order to remain consistent with the rest of cosmological observations, only part of the dar...

We discuss a few scenarios with decaying DarkMatter and their prospect for detection at the LHC. First we present a simple minimal scenario, where DarkMatter is produced from the decay of a heavier colored or EW charged scalar via the FIMP or SuperWIMP mechanisms, then we discuss supersymmetric scenarios with RPV and gravitino DM, in particular a scenario allowing for simultaneous generation of DM and baryogenesis at a (relatively) low scale.

Weakly interacting slim particles (WISPs) such as hidden photons (HP) and axion-like particles (ALPs) have been proposed as cold darkmatter candidates. They might be produced non-thermally via the misalignment mechanism, similarly to cold axions. In this talk we review the main processes of thermalisation of HP and we compute the parameter space that may survive as cold darkmatter population until today. Our findings are quite encouraging for experimental searches in the laboratory in the near future.

Direct detection of darkmatter with directional sensitivity has the potential to discriminate the darkmatter velocity distribution. Especially, it will be suitable to discriminate isotropic distribution from anisotropic one. Analyzing data produced with Monte-Carlo simulation, required conditions for the discrimination is estimated. If energy threshold of detector is optimized, $O(10^3-10^4)$ event number is required to discriminate the anisotropy.

We reexamine a renormalizable model of a fermionic darkmatter with a gauge singlet Dirac fermion and a real singlet scalar which can ameliorate the scalar mass hierarchy problem of the Standard Model (SM). Our model setup is the minimal extension of the SM for which a realistic darkmatter (DM) candidate is provided and the cancellation of one-loop quadratic divergence to the scalar masses can be achieved by the Veltman condition (VC) simultaneously. This model extension, although renormaliz...

Weakly interacting slim particles (WISPs) such as hidden photons (HP) and axion-like particles (ALPs) have been proposed as cold darkmatter candidates. They might be produced non-thermally via the misalignment mechanism, similarly to cold axions. In this talk we review the main processes of thermalisation of HP and we compute the parameter space that may survive as cold darkmatter population until today. Our findings are quite encouraging for experimental searches in the laboratory in the near future.

The recent determination of the darkmatter density in the universe by the WMAP satellite has brought new attention to the interplay of results from particle physics experiments at accelerators and from cosmology. In this paper we discuss the prospects for finding direct evidence for a candidate darkmatter particle at the LHC and the measurements which would be crucial for testing its compatibility with the cosmology data. (topical review)

We study a simplified model of top-flavoured darkmatter in the framework of Dark Minimal Flavour Violation. In this setup the coupling of the darkmatter flavour triplet to right-handed up-type quarks constitutes the only new source of flavour and CP violation. The parameter space of the model is restricted by LHC searches with missing energy final states, by neutral D meson mixing data, by the observed darkmatter relic abundance, and by the absence of signal in direct detection experiments. We consider all of these constraints in turn, studying their implications for the allowed parameter space. Imposing the mass limits and coupling benchmarks from collider searches, we then conduct a combined analysis of all the other constraints, revealing their non-trivial interplay. Especially interesting is the combination of direct detection and relic abundance constraints, having a severe impact on the structure of the darkmatter coupling matrix. We point out that future bounds from upcoming direct detection experiments, such as XENON1T, XENONnT, LUX-ZEPLIN, and DARWIN, will exclude a large part of the parameter space and push the DM mass to higher values.

In models of coupled dark energy and darkmatter the mass of the darkmatter particle depends on the cosmological evolution of the dark energy field. In this Letter we exemplify in a simple model the effects of this mass variation on the relic abundance of cold darkmatter

We provide a detailed analysis of how bosonic darkmatter "condensates" interact with compact stars, extending significantly the results of a recent Letter [1]. We focus on bosonic fields with mass mB , such as axions, axion-like candidates and hidden photons. Self-gravitating bosonic fields generically form "breathing" configurations, where both the spacetime geometry and the field oscillate, and can interact and cluster at the center of stars. We construct stellar configurations formed by a perfect fluid and a bosonic condensate, and which may describe the late stages of darkmatter accretion onto stars, in dark-matter-rich environments. These composite stars oscillate at a frequency which is a multiple of f =2.5 ×1014(mBc2/eV ) Hz . Using perturbative analysis and numerical relativity techniques, we show that these stars are generically stable, and we provide criteria for instability. Our results also indicate that the growth of the darkmatter core is halted close to the Chandrasekhar limit. We thus dispel a myth concerning darkmatter accretion by stars: darkmatter accretion does not necessarily lead to the destruction of the star, nor to collapse to a black hole. Finally, we argue that stars with long-lived bosonic cores may also develop in other theories with effective mass couplings, such as (massless) scalar-tensor theories.

Astronomical observations from small galaxies to the largest scales in the universe can be consistently explained by the simple idea of darkmatter. The nature of darkmatter is however still unknown. Empirically it cannot be any of the known particles, and many theories postulate it as a new elementary particle. Searches for darkmatter particles are under way: production at high-energy accelerators, direct detection through darkmatter-nucleus scattering, indirect detection through cosmic rays, gamma rays, or effects on stars. Particle darkmatter searches rely on observing an excess of events above background, and a lot of controversies have arisen over the origin of observed excesses. With the new high-quality cosmic ray measurements from the AMS-02 experiment, the major uncertainty in modeling cosmic ray fluxes is in the nuclear physics cross sections for spallation and fragmentation of cosmic rays off interstellar hydrogen and helium. The understanding of direct detection backgrounds is limited by poor knowledge of cosmic ray activation in detector materials, with order of magnitude differences between simulation codes. A scarcity of data on nucleon spin densities blurs the connection between darkmatter theory and experiments. What is needed, ideally, are more and better measurements of spallation cross sections relevant to cosmic rays and cosmogenic activation, and data on the nucleon spin densities in nuclei

Astrophysical and cosmological observations do not require the darkmatter particles to be absolutely stable. If they are indeed unstable, their decay into positrons might occur at a sufficiently large rate to allow the indirect detection of darkmatter through an anomalous contribution to the cosmic positron flux. In this paper we discuss the implications of the excess in the positron fraction recently reported by the PAMELA collaboration for the scenario of decaying darkmatter. To this end, we have performed a model-independent analysis of possible signatures by studying various decay channels in the case of both a fermionic and a scalar darkmatter particle. We find that the steep rise in the positron fraction measured by PAMELA at energies larger than 10 GeV can naturally be accommodated in several realizations of the decaying darkmatter scenario. The data point toward a rather heavy darkmatter particle, m DM ∼> 300 GeV, which preferentially decays directly into first or second generation charged leptons with a lifetime τ DM ∼ 10 26 s

We study in detail the conditions to generate the baryon asymmetry of the universe from the annihilation of darkmatter. This scenario requires a low energy mechanism for thermal baryogenesis, hence we first discuss some of these mechanisms together with the specific constraints due to the connection with the darkmatter sector. Then we show that, contrary to what stated in previous studies, it is possible to generate the cosmological asymmetry without adding a light sterile dark sector, both in models with violation and with conservation of B−L. In addition, one of the models we propose yields some connection to neutrino masses

We present a novel mechanism for generating both the baryon and darkmatter densities of the Universe. A new Dirac fermion X carrying a conserved baryon number charge couples to the standard model quarks as well as a GeV-scale hidden sector. CP-violating decays of X, produced nonthermally in low-temperature reheating, sequester antibaryon number in the hidden sector, thereby leaving a baryon excess in the visible sector. The antibaryonic hidden states are stable darkmatter. A spectacular signature of this mechanism is the baryon-destroying inelastic scattering of darkmatter that can annihilate baryons at appreciable rates relevant for nucleon decay searches.

We present a novel mechanism for generating both the baryon and darkmatter densities of the Universe. A new Dirac fermion X carrying a conserved baryon number charge couples to the standard model quarks as well as a GeV-scale hidden sector. CP-violating decays of X, produced nonthermally in low-temperature reheating, sequester antibaryon number in the hidden sector, thereby leaving a baryon excess in the visible sector. The antibaryonic hidden states are stable darkmatter. A spectacular signature of this mechanism is the baryon-destroying inelastic scattering of darkmatter that can annihilate baryons at appreciable rates relevant for nucleon decay searches.

We have studied the phenomenology of darkmatter at the ILC and cosmic positron experiments based on model-independent approach. We have found a strong correlation between darkmatter signatures at the ILC and those in the indirect detection experiments of darkmatter. Once the darkmatter is discovered in the ...

Abstract. We have studied the phenomenology of darkmatter at the ILC and cosmic positron experiments based on model-independent approach. We have found a strong correlation between darkmatter signatures at the ILC and those in the indirect detec- tion experiments of darkmatter. Once the darkmatter is discovered ...

In this talk I contrast three different particle darkmatter candidates, all motivated by new physics beyond the Standard Model: supersymmetric darkmatter, Kaluza-Klein darkmatter, and scalar darkmatter. I then discuss the prospects for their discovery and identification in both direct detection as well as collider experiments

In this review article we give a brief overview on some recent progress in quark pairings in dense quark/nuclear matter mostly developed in the past five years. We focus on following aspects in particular: the BCS-BEC crossover in the CSC phase, the baryon formation and dissociation in dense quark/nuclear matter, the Ginzburg-Landau theory for three-flavor dense matter with U A (1) anomaly, and the collective and Nambu-Goldstone modes for the spin-one CSC. (physics of elementary particles and fields)

In some darkmatter models, the coupling of the darkmatter particle to the standard model Higgs determines the darkmatter relic density while it is also consistent with darkmatter direct-detection experiments. On the other hand, the seesaw model for generating the neutrino masses probably arises from a spontaneous symmetry breaking of global lepton number. The darkmatter particle thus can significantly annihilate into massless Majorons when the lepton number-breaking scale and hence the seesaw scale are near the electroweak scale. This leads to an interesting interplay between neutrino physics and darkmatter physics, and the annihilation mode has an interesting implication on darkmatter searches.

We extend the formalism of darkmatter directional detection to arbitrary one-body darkmatter-nucleon interactions. The new theoretical framework generalizes the one currently used, which is based on 2 types of darkmatter-nucleon interaction only. It includes 14 darkmatter-nucleon interaction operators, 8 isotope-dependent nuclear response functions, and the Radon transform of the first 2 moments of the darkmatter velocity distribution. We calculate the recoil energy spectra at darkmatter directional detectors made of CF 4 , CS 2 and 3 He for the 14 darkmatter-nucleon interactions, using nuclear response functions recently obtained through numerical nuclear structure calculations. We highlight the new features of the proposed theoretical framework, and present our results for a spherical darkmatter halo and for a stream of darkmatter particles. This study lays the foundations for model independent analyses of darkmatter directional detection experiments

It is shown that the theory of darkmatter can be derived from the first principles. Particles representing a new form of matter gravitate but do not interact electromagnetically, strongly and weakly with the known elementary particles. Physics of these particles is defined by the Planck scales.

We consider a cosmological model of the late universe constituted by standard cold darkmatter plus a dark energy component with constant equation of state w and constant effective speed of sound. By neglecting fluctuations in the dark energy component, we obtain an equation describing the evolution of sub-horizon cold darkmatter perturbations through the epoch of darkmatter-dark energy equality. We explore its analytic solutions and calculate an exact w-dependent correction for the darkmatter growth function, logarithmic growth function and growth index parameter through the epoch considered. We test our analytic approximation with the numerical solution and find that the discrepancy is less than 1% for 0k = during the cosmic evolution up to a = 100

Ordinary baryonic particles (such as protons and neutrons) account for only one-sixth of the total matter in the Universe. The remainder is a mysterious 'darkmatter' component, which does not interact via electromagnetism and thus neither emits nor reflects light. As darkmatter cannot be seen directly using traditional observations, very little is currently known about its properties. It does interact via gravity, and is most effectively probed through gravitational lensing: the deflection of light from distant galaxies by the gravitational attraction of foreground mass concentrations. This is a purely geometrical effect that is free of astrophysical assumptions and sensitive to all matter - whether baryonic or dark. Here we show high-fidelity maps of the large-scale distribution of darkmatter, resolved in both angle and depth. We find a loose network of filaments, growing over time, which intersect in massive structures at the locations of clusters of galaxies. Our results are consistent with predictions of gravitationally induced structure formation, in which the initial, smooth distribution of darkmatter collapses into filaments then into clusters, forming a gravitational scaffold into which gas can accumulate, and stars can be built. (authors)

Ordinary baryonic particles (such as protons and neutrons) account for only one-sixth of the total matter in the Universe. The remainder is a mysterious 'darkmatter' component, which does not interact via electromagnetism and thus neither emits nor reflects light. As darkmatter cannot be seen directly using traditional observations, very little is currently known about its properties. It does interact via gravity, and is most effectively probed through gravitational lensing: the deflection of light from distant galaxies by the gravitational attraction of foreground mass concentrations. This is a purely geometrical effect that is free of astrophysical assumptions and sensitive to all matter - whether baryonic or dark. Here we show high-fidelity maps of the large-scale distribution of darkmatter, resolved in both angle and depth. We find a loose network of filaments, growing over time, which intersect in massive structures at the locations of clusters of galaxies. Our results are consistent with predictions of gravitationally induced structure formation, in which the initial, smooth distribution of darkmatter collapses into filaments then into clusters, forming a gravitational scaffold into which gas can accumulate, and stars can be built. (authors)

Ordinary baryonic particles (such as protons and neutrons) account for only one-sixth of the total matter in the Universe. The remainder is a mysterious 'darkmatter' component, which does not interact via electromagnetism and thus neither emits nor reflects light. As darkmatter cannot be seen directly using traditional observations, very little is currently known about its properties. It does interact via gravity, and is most effectively probed through gravitational lensing: the deflection of light from distant galaxies by the gravitational attraction of foreground mass concentrations. This is a purely geometrical effect that is free of astrophysical assumptions and sensitive to all matter--whether baryonic or dark. Here we show high-fidelity maps of the large-scale distribution of darkmatter, resolved in both angle and depth. We find a loose network of filaments, growing over time, which intersect in massive structures at the locations of clusters of galaxies. Our results are consistent with predictions of gravitationally induced structure formation, in which the initial, smooth distribution of darkmatter collapses into filaments then into clusters, forming a gravitational scaffold into which gas can accumulate, and stars can be built.

We discuss the evolution of density perturbations of darkmatter and dark energy in cosmological models which admit future singularities in a finite time. Up to now geometrical tests of the evolution of the universe do not differentiate between singular universes and ΛCDM scenario. We solve perturbation equations using the gauge invariant formalism. The analysis shows that the detailed reconstruction of the evolution of perturbations within singular cosmologies, in the dark sector, can exhibit important differences between the singular universes models and the ΛCDM cosmology. This is encouraging for further examination and gives hope for discriminating between those models with future galaxy weak lensing experiments like the Dark Energy Survey (DES) and Euclid or CMB observations like PRISM and CoRE

Limits on the value of critical temperature of the quark-hadron phase transition, evaluated by chiral perturbation calculations, are discussed in the frame of primordial nucleosynthesis. The yield of lithium is compatible with the Pop II data in approximately the same range as in the case of homogeneous baryonic density models. Taking into account various factors in the search for the initial abundance of the cosmological isotopes, it appears very likely that most of the baryonic matter is not luminous and that most of the darkmatter is non-baryonic. However pushing all the uncertainties to their extremes, it seems also that we do not necessarily require baryonic darkmatter and, we do not necessarily require non-baryonic darkmatter. The uncertainty in the value of the Hubble parameter remains one of the largest source of uncertainty in this analysis

In this Report we discuss the four complementary searches for the identity of darkmatter: direct detection experiments that look for darkmatter interacting in the lab, indirect detection experiments that connect lab signals to darkmatter in our own and other galaxies, collider experiments that elucidate the particle properties of darkmatter, and astrophysical probes sensitive to non-gravitational interactions of darkmatter. The complementarity among the different darkmatter searches is discussed qualitatively and illustrated quantitatively in several theoretical scenarios. Our primary conclusion is that the diversity of possible darkmatter candidates requires a balanced program based on all four of those approaches.

The standard model could be self-consistent up to the Planck scale according to the present measurements of the Higgs boson mass and top quark Yukawa coupling. It is therefore possible that new physics is only coupled to the standard model through Planck suppressed higher dimensional operators. In this case the weakly interacting massive particle miracle is a mirage, and instead minimality as dictated by Occam's razor would indicate that darkmatter is related to the Planck scale, where quantum gravity is anyway expected to manifest itself. Assuming within this framework that darkmatter is a Planckian interacting massive particle, we show that the most natural mass larger than 0.01M_{p} is already ruled out by the absence of tensor modes in the cosmic microwave background (CMB). This also indicates that we expect tensor modes in the CMB to be observed soon for this type of minimal darkmatter model. Finally, we touch upon the Kaluza-Klein graviton mode as a possible realization of this scenario within UV complete models, as well as further potential signatures and peculiar properties of this type of darkmatter candidate. This paradigm therefore leads to a subtle connection between quantum gravity, the physics of primordial inflation, and the nature of darkmatter.

In this paper we study a real scalar field as a possible candidate to explain the darkmatter in the universe. In the context of a free scalar field with quadratic potential, we have used Union 2.1 SN Ia observational data jointly with a Planck prior over the darkmatter density parameter to set a lower limit on the darkmatter mass as m ≥0.12 H {sub 0}{sup -1} eV ( c = h-bar =1). For the recent value of the Hubble constant indicated by the Hubble Space Telescope, namely H {sub 0}=73±1.8 km s{sup -1}Mpc{sup -1}, this leads to m ≥1.56×10{sup -33} eV at 99.7% c.l. Such value is much smaller than m ∼ 10{sup -22} eV previously estimated for some models. Nevertheless, it is still in agreement with them once we have not found evidences for a upper limit on the scalar field darkmatter mass from SN Ia analysis. In practice, it confirms free real scalar field as a viable candidate for darkmatter in agreement with previous studies in the context of density perturbations, which include scalar field self interaction.

A model of the dark sector where O(few GeV) mass darkmatter particles χ couple to a lighter dark force mediator V, m_{V}≪m_{χ}, is motivated by the recently discovered mismatch between simulated and observed shapes of galactic halos. Such models, in general, provide a challenge for direct detection efforts and collider searches. We show that for a large range of coupling constants and masses, the production and decay of the bound states of χ, such as 0^{-+} and 1^{--} states, η_{D} and ϒ_{D}, is an important search channel. We show that e^{+}e^{-}→η_{D}+V or ϒ_{D}+γ production at B factories for α_{D}>0.1 is sufficiently strong to result in multiple pairs of charged leptons and pions via η_{D}→2V→2(l^{+}l^{-}) and ϒ_{D}→3V→3(l^{+}l^{-}) (l=e,μ,π). The absence of such final states in the existing searches performed at BABAR and Belle sets new constraints on the parameter space of the model. We also show that a search for multiple bremsstrahlung of dark force mediators, e^{+}e^{-}→χχ[over ¯]+nV, resulting in missing energy and multiple leptons, will further improve the sensitivity to self-interacting darkmatter.

A substantial body of observational evidence indicates that the universe contains much more material than we observe directly via photons of any wavelength. The existence of this "missing" mass or "dark" matter is inferred by its gravitational effects on the luminous material. Accepting the existence of darkmatter has profoundly shaken our understanding in most areas of cosmology. If it exists at the lowest densities measured it is hard to understand in detail the creation of the elements in the early universe. If moderate density values are correct, then we have trouble understanding how the universe came to have so much structure on large scales. If the largest densities are correct, then darkmatter is not ordinary matter, but must be something exotic like a new fundamental particle. We would like to measure the properties of the darkmatter directly. Supposing that the darkmatter consists of a WIMP, that was in thermal equilibrium in the early universe, we have built an experiment to detect darkmatter directly by elastic scattering with germanium or silicon nuclei. Our detectors are large (~ 200 g) calorimeters that can discriminate between interactions with the electrons, due to background photons and beta particles, and interactions with the nuclei, due to WIMPs and background neutrons. The detectors operate at low temperatures (~ 20 mK) in a specially constructed cryostat. To reduce the rate of background events to a manageable level, the detectors and cryostat have been constructed out of selected materials and properly shielded. This dissertation discusses the properties of the hypothetical WIMPs, the detectors, cryostat, and shielding system, and finally, the analysis methods.new fundamental particle, a

In this article, we examine a model which proposes a common explanation for the presence of additional attractive gravitational effects - generally considered to be due to darkmatter - in galaxies and in clusters, and for the presence of a repulsive effect at cosmological scales - generally taken as an indication of the presence of dark energy. We therefore consider the behavior of a so-called dark fluid based on a complex scalar field with a conserved U(1)-charge and associated to a specific potential, and show that it can at the same time account for darkmatter in galaxies and in clusters, and agree with the cosmological observations and constraints on dark energy and darkmatter

We show that supersymmetric ''Dark Force'' models with gravity mediation are viable. To this end, we analyse a simple supersymmetric hidden sector model that interacts with the visible sector via kinetic mixing of a light Abelian gauge boson with the hypercharge. We include all induced interactions with the visible sector such as neutralino mass mixing and the Higgs portal term. We perform a detailed parameter space scan comparing the produced darkmatter relic abundance and direct detection cross-sections to current experiments. (orig.)

Astrophysical and cosmological observations do not require the darkmatter particles to be absolutely stable. If they are indeed unstable, their decay into Standard Model particles might occur at a sufficiently large rate to allow the indirect detection of darkmatter through an anomalous contribution to the high energy cosmic ray fluxes. We analyze the implications of the excess in the total electron plus positron flux and the positron fraction reported by the Fermi and PAMELA collaborations, respectively, for the scenario of decaying darkmatter. We also discuss the constraints on this scenario from measurements of other cosmic ray species and the predictions for the diffuse gamma ray flux and the neutrino flux. In particular, we expect a sizable dipole-like anisotropy which may be observed in the near future by the Fermi-LAT.

Searches for darkmatter imprints are one of the most active areas of current research. We focus here on light fields with mass m_{B}, such as axions and axionlike candidates. Using perturbative techniques and full-blown nonlinear numerical relativity methods, we show the following. (i) Darkmatter can pile up in the center of stars, leading to configurations and geometries oscillating with a frequency that is a multiple of f=2.5×10^{14}(m_{B}c^{2}/eV) Hz. These configurations are stable throughout most of the parameter space, and arise out of credible mechanisms for dark-matter capture. Stars with bosonic cores may also develop in other theories with effective mass couplings, such as (massless) scalar-tensor theories. We also show that (ii) collapse of the host star to a black hole is avoided by efficient gravitational cooling mechanisms.

We propose a novel method utilizing stellar kinematic data to detect low-mass substructure in the Milky Way's darkmatter halo. By probing characteristic wakes that a passing darkmatter subhalo leaves in the phase-space distribution of ambient halo stars, we estimate sensitivities down to subhalo masses of ∼10^{7} M_{⊙} or below. The detection of such subhalos would have implications for darkmatter and cosmological models that predict modifications to the halo-mass function at low halo masses. We develop an analytic formalism for describing the perturbed stellar phase-space distributions, and we demonstrate through idealized simulations the ability to detect subhalos using the phase-space model and a likelihood framework. Our method complements existing methods for low-mass subhalo searches, such as searches for gaps in stellar streams, in that we can localize the positions and velocities of the subhalos today.

We show that left-right symmetric models can easily accommodate stable TeV-scale darkmatter particles without the need for an ad hoc stabilizing symmetry. The stability of a newly introduced multiplet either arises accidentally as in the minimal darkmatter framework or comes courtesy of the remaining unbroken Z_{2} subgroup of B-L. Only one new parameter is introduced: the mass of the new multiplet. As minimal examples, we study left-right fermion triplets and quintuplets and show that they can form viable two-component darkmatter. This approach is, in particular, valid for SU(2)×SU(2)×U(1) models that explain the recent diboson excess at ATLAS in terms of a new charged gauge boson of mass 2 TeV.

We propose a novel method utilizing stellar kinematic data to detect low-mass substructure in the Milky Way's darkmatter halo. By probing characteristic wakes that a passing darkmatter subhalo leaves in the phase-space distribution of ambient halo stars, we estimate sensitivities down to subhalo masses of ˜107 M⊙ or below. The detection of such subhalos would have implications for darkmatter and cosmological models that predict modifications to the halo-mass function at low halo masses. We develop an analytic formalism for describing the perturbed stellar phase-space distributions, and we demonstrate through idealized simulations the ability to detect subhalos using the phase-space model and a likelihood framework. Our method complements existing methods for low-mass subhalo searches, such as searches for gaps in stellar streams, in that we can localize the positions and velocities of the subhalos today.

We examine massive neutrino (hot darkmatter) models for large-scale structure in which the density perturbations are produced by randomly distributed relic seeds and by inflation. Power spectra, streaming velocities, and the Sachs-Wolfe quadrupole fluctuation are derived for this model. We find that the pure seeded hot darkmatter model without inflation produces Sachs-Wolfe fluctuations far smaller than those seen by COBE. With the addition of inflationary perturbations, fluctuations consistent with COBE can be produced. The COBE results set the normalization of the inflationary component, which determines the large-scale (about 50/h Mpc) streaming velocities. The normalization of the seed power spectrum is a free parameter, which can be adjusted to obtain the desired fluctuations on small scales. The power spectra produced are very similar to those seen in mixed hot and cold darkmatter models.

One of the most interesting mysteries of astrophysics is the puzzle of darkmatter. Although numerous techniques have been explored and developed to detect this elusive substance, its nature remains unknown. One such method uses large high-energy neutrino telescopes to look for the annihilation products of darkmatter annihilations. In this paper, we briefly review this technique. We describe the calculations used to find the rate of capture of WIMPs in the Sun or Earth and the spectrum of neutrinos produced in the resulting darkmatter annihilations. We will discuss these calculations within the context of supersymmetry and models with universal extra dimensions, the lightest supersymmetric particle and lightest Kaluza-Klein particle providing the WIMP candidate in these cases, respectively. We will also discuss the status of some of the experiments relevant to these searches: AMANDA, IceCube and ANTARES

It has recently been shown that the electroweak baryogenesis mechanism is feasible in Standard Model extensions containing extra fermions with large Yukawa couplings. We show here that the lightest of these fermionic fields can naturally be a good candidate for cold darkmatter. We find regions in the parameter space where the thermal relic abundance of this particle is compatible with the darkmatter density of the Universe as determined by the WMAP experiment. We study direct and indirect darkmatter detection for this model and compare with current experimental limits and prospects for upcoming experiments. We find, contrary to the standard lore, that indirect detection searches are more promising than direct ones, and they already exclude part of the parameter space

We explore the possibility that fermionic darkmatter undergoes a BCS transition to form a superfluid. This requires an attractive interaction between fermions and we describe a possible source of this interaction induced by torsion. We describe the gravitating fermion system with the Bogoliubov-de Gennes formalism in the local density approximation. We solve the Poisson equation along with the equations for the density and gap energy of the fermions to find a self-gravitating, superfluid solution for darkmatter halos. In order to produce halos the size of dwarf galaxies, we require a particle mass of ∼ 200 eV. We find a maximum attractive coupling strength before the halo becomes unstable. If darkmatter halos do have a superfluid component, this raises the possibility that they contain vortex lines.

The fundamental properties of darkmatter, such as its mass, self-interaction, and coupling to other particles, can have a major impact on the evolution of cosmological density fluctuations on small length scales. Strong gravitational lenses have long been recognized as powerful tools to study the darkmatter distribution on these small subgalactic scales. In this talk, we discuss how gravitationally lensed quasars and extended lensed arcs could be used to probe non minimal darkmatter models. We comment on the possibilities enabled by precise astrometry, deep imaging, and time delays to extract information about mass substructures inside lens galaxies. To this end, we introduce a new lensing statistics that allows for a robust diagnostic of the presence of perturbations caused by substructures. We determine which properties of mass substructures are most readily constrained by lensing data and forecast the constraining power of current and future observations.

For a wide range of models, darkmatter can interact with QCD gluons via chromo-Rayleigh interactions. We point out that the Large Hadron Collider (LHC), as a gluon machine, provides a superb probe of such interactions. In this paper, we introduce simplified models to UV-complete two effective darkmatter chromo-Rayleigh interactions and identify the corresponding collider signatures, including four jets or a pair of di-jet resonances plus missing transverse energy. After performing collider studies for both the 8 TeV and 14 TeV LHC, we find that the LHC can be more sensitive to darkmatter chromo-Rayleigh interactions than direct detection experiments and thus provides the best opportunity for future discovery of this class of models.

We investigate a perturbative extension of the Standard Model featuring elementary pseudo-Goldstone Higgs and darkmatter particles. These are two of the five Goldstone bosons parametrising the SU(4)/Sp(4) coset space. They acquire masses, and therefore become pseudo-Goldstone bosons, due...... of the theory, the quantum corrections are precisely calculable. The remaining pseudo-Goldstone boson is identified with the darkmatter candidate because it is neutral with respect to the Standard Model and stable. By a direct comparison with the Large Hadron Collider experiments, the model is found...... to be phenomenologically viable. Furthermore the darkmatter particle leads to the observed thermal relic density while respecting the most stringent current experimental constraints....

This paper is about rediscovering darkmatter (DM) in galaxies before the year 1970. It is an Italy-Malaysia Astroproject (SISSA-Radio Cosmology Research group), introducing to the field of DM. Investigations about the rotation curve (RC) of NGC 5055 or the Sunflower Galaxy at that time showed that there was a distinct possibility that they had the knowledge and also the theory of gravitation to initiate the study of darkmatter. NGC 5055 was chosen because of its good kinematical and photometric data. Information of the surface brightness of this spiral galaxy will determine the disk length scale, RD. Using this RD and by fitting the RC data of NGC 5055 with the velocity profile of the Freeman's disk, we look at the results to conclude whether there are signs of darkmatter in the Sunflower Galaxy.

We study thermal neutralino darkmatter in an effective field theory extension of the MSSM, called ''Beyond the MSSM'' (BMSSM) in Dine, Seiberg and Thomas (2007). In this class of effective field theories, the field content of the MSSM is unchanged, but the little hierarchy problem is alleviated by allowing small corrections to the Higgs/higgsino part of the Lagrangian. We perform parameter scans and compute the darkmatter relic density. The light higgsino LSP scenario is modified the most; we find new regions of parameter space compared to the standard MSSM. This involves interesting interplay between the WMAP darkmatter bounds and the LEP chargino bound. We also find some changes for gaugino LSPs, partly due to annihilation through a Higgs resonance, and partly due to coannihilation with light top squarks in models that are ruled in by the new effective terms

We analyze the darkmatter problem in the context of brane cosmology. We investigate the impact of the non-conventional brane cosmology on the relic abundance of non-relativistic stable particles in high and low reheating temperature scenarios. We show that in case of high reheating temperature, the brane cosmology may enhance the darkmatter relic density by many order of magnitudes and a stringent lower bound on the five dimensional scale is obtained. We also consider low reheating temperature scenarios with chemical equilibrium and non-equilibrium. We emphasize that in non-equilibrium case, the resulting relic density is very small. While with equilibrium, it is increased by a factor of O(10 2 ) with respect to the standard thermal production. Therefore, darkmatter particles with large cross section, which is favored by detection expirements, can be consistent with the recent relic density observational limits

Full Text Available In a theory containing scalar fields, a generic consequence is a formation of scalar condensates during cosmic inflation. The displacement of scalar fields out from their vacuum values sets specific initial conditions for post-inflationary dynamics and may lead to significant observational ramifications. In this work, we investigate how these initial conditions affect the generation of darkmatter in the class of portal scenarios where the standard model fields feel new physics only through Higgs-mediated couplings. As a representative example, we will consider a $ Z_2 $ symmetric scalar singlet $ s $ coupled to Higgs via $ \\lambda \\Phi ^\\dagger \\Phi s^2 $. This simple extension has interesting consequences as the singlet constitutes a darkmatter candidate originating from non-thermal production of singlet particles out from a singlet condensate, leading to a novel interplay between inflationary dynamics and darkmatter properties.

The WIMPzilla hypothesis is that the darkmatter is a super-weakly-interacting and superheavy particle. Conventionally, the WIMPzilla abundance is set by gravitational particle production during or at the end of inflation. In this study we allow the WIMPzilla to interact directly with Standard Model fields through the Higgs portal, and we calculate the thermal production (freeze-in) of WIMPzilla darkmatter from the annihilation of Higgs boson pairs in the plasma. The two particle-physics model parameters are the WIMPzilla mass and the Higgs-WIMPzilla coupling. The two cosmological parameters are the reheating temperature and the expansion rate of the universe at the end of inflation. We delineate the regions of parameter space where either gravitational or thermal production is dominant, and within those regions we identify the parameters that predict the observed darkmatter relic abundance. Allowing for thermal production opens up the parameter space, even for Planck-suppressed Higgs-WIMPzilla interactions.

Experiments performed over the last two years have been very successful in drastically reducing the number of viable elementary particles that could possibly constitute the darkmatter that dominates the large-scale gravitational dynamics of astronomical systems. The candidates that survive are the light neutrinos, the axion, and a supersymmetric particle with carefully chosen parameters called the neutralino. Baryonic darkmatter, which might contribute not insignificantly over small scales, is perhaps present in the form of brown dwarfs, and a search for these is under way. In this article, the astrophysical studies which bear on the density and the phase-space structure of the dark-matter particles are reviewed and the implications of the various direct and indirect searches for these particles are discussed and, finally, alternative suggestions for the candidates and directions for further searches are pointed out. (author). 35 refs., 29 figs

Recent developments in bigravity allow one to construct consistent theories of interacting spin-2 particles that are free of ghosts. In this framework, we propose an elementary spin-2 darkmatter candidate with a mass well below the TeV scale. We show that, in a certain regime where the interactions induced by the spin-2 fields do not lead to large departures from the predictions of general relativity, such a light darkmatter particle typically self-interacts and undergoes self-annihilations via 3-to-2 processes. We discuss its production mechanisms and also identify the regions of the parameter space where self-interactions can alleviate the discrepancies at small scales between the predictions of the collisionless darkmatter paradigm and cosmological N-body simulations.

The quest for the nature of darkmatter has reached a historical point in time, with several different and complementary experiments on the verge of conclusively exploring large portions of the parameter space of the most theoretically compelling particle darkmatter models. This focus issue on darkmatter and particle physics brings together a broad selection of invited articles from the leading experimental and theoretical groups in the field. The leitmotif of the collection is the need for a multi-faceted search strategy that includes complementary experimental and theoretical techniques with the common goal of a sound understanding of the fundamental particle physical nature of darkmatter. These include theoretical modelling, high-energy colliders and direct and indirect searches. We are confident that the works collected here present the state of the art of this rapidly changing field and will be of interest to both experts in the topic of darkmatter as well as to those new to this exciting field. Focus on DarkMatter and Particle Physics Contents DARKMATTER AND ASTROPHYSICS Scintillator-based detectors for darkmatter searches I S K Kim, H J Kim and Y D Kim Cosmology: small-scale issues Joel R Primack Big Bang nucleosynthesis and particle darkmatter Karsten Jedamzik and Maxim Pospelov Particle models and the small-scale structure of darkmatter Torsten Bringmann DARKMATTER AND COLLIDERS Darkmatter in the MSSM R C Cotta, J S Gainer, J L Hewett and T G Rizzo The role of an e+e- linear collider in the study of cosmic darkmatter M Battaglia Collider, direct and indirect detection of supersymmetric darkmatter Howard Baer, Eun-Kyung Park and Xerxes Tata INDIRECT PARTICLE DARKMATTER SEARCHES:EXPERIMENTS PAMELA and indirect darkmatter searches M Boezio et al An indirect search for darkmatter using antideuterons: the GAPS experiment C J Hailey Perspectives for indirect darkmatter search with AMS-2 using cosmic-ray electrons and positrons B Beischer, P von

We attempt to answer whether neutrinos and antineutrinos, such as those in the cosmic neutrino background, would clusterize among themselves or even with other dark-matter particles, under certain time span, say 1 Gyr. With neutrino masses in place, the similarity with the ordinary matter increases and so is our confidence for neutrino clustering if time is long enough. In particular, the clusterings could happen with some seeds (cf. see the text for definition), the chance in the dark-matter...

Directional darkmatter detection attempts to measure the direction of motion of nuclei recoiling after having interacted with darkmatter particles in the halo of our Galaxy. Due to Earth's motion with respect to the Galaxy, the darkmatter flux is concentrated around a preferential direction. An anisotropy in the recoil direction rate is expected as an unmistakable signature of darkmatter. The average nuclear recoil direction is expected to coincide with the average direction of darkmatter particles arriving to Earth. Here we point out that for a particular type of darkmatter, inelastic exothermic darkmatter, the mean recoil direction as well as a secondary feature, a ring of maximum recoil rate around the mean recoil direction, could instead be opposite to the average darkmatter arrival direction. Thus, the detection of an average nuclear recoil direction opposite to the usually expected direction would constitute a spectacular experimental confirmation of this type of darkmatter.

If standard gravitational theory is correct, then most of the matter in the universe is in an unidentified form which does not emit enough light to have been detected by current instrumentation. This proceedings was devoted to a discussion of the so-called ''missing matter'' problem in the universe. The goal of the School was to make current research work on unseen matter accessible to students or facilities without prior experience in this area. Due to the pedagogical nature of the School and the strong interactions between students and the lecturers, the written lectures included in this volume often contain techniques and explanations not found in more formal journal publications

In this paper, an idea on darkmatter nonconcentric with luminous matter is proposed. This case could influence the rotation curve of galaxy differently in its different direction. Recently, Rubin and Ford's observation on rotation curve of Hickson 88a has been explained by means of the idea. Some possible observational predictions have also been given. (author)

We propose a dark-matter model in which the dark sector is gauged under a new SU(2) group. The dark sector consists of SU(2) dark gauge fields, two triplet dark Higgs fields, and two dark fermion doublets (dark-matter candidates in this model). The dark sector interacts with the standard model sector through kinetic and mass mixing operators. The model explains both PAMELA and Fermi LAT data very well and also satisfies constraints from both the dark-matter relic density and standard model precision observables. The phenomenology of the model at the LHC is also explored.

The gravitino in models with a small violation of R-parity is a well-motivated decaying darkmatter candidate that leads to a cosmological scenario that is consistent with big bang nucleosynthesis and thermal leptogenesis. The gravitino lifetime is cosmologically long-lived since its decays are suppressed by the Planck-scale as well as the small R-parity violating parameter. We discuss the signals in different cosmic-ray species coming from the decay of gravitino darkmatter, namely gamma rays, positrons, antiprotons, antideuterons and neutrinos. Comparison to cosmic-ray data can be used to constrain the parameters of the model. (orig.)

We update the parameter spaces for both a real and complex scalar darkmatter via the Higgs portal. In the light of constraints arising from the LUX 2016 data, the latest Higgs invisible decay and the gamma ray spectrum, the darkmatter resonant mass region is further restricted to a narrow window between 54.9−62.3 GeV in both cases, and its large mass region is excluded until 834 GeV and 3473 GeV for the real and complex scalar, respectively.

We update the parameter spaces for both a real and complex scalar darkmatter via the Higgs portal. In the light of constraints arising from the LUX 2016 data, the latest Higgs invisible decay and the gamma ray spectrum, the darkmatter resonant mass region is further restricted to a narrow window between 54.9−62.3 GeV in both cases, and its large mass region is excluded until 834 GeV and 3473 GeV for the real and complex scalar, respectively.

As evidenced by the numerous contributions on the topic at this meeting, the IX International Conference on Interconnections between Particle Physics and Cosmology (PPC2015), the direct detection of darkmatter remains as one of the highest priorities in both particle physics and cosmology. In 2013 the LUX direct darkmatter search collaboration reported the most stringent constraints to-date on the spin-independent WIMP–nucleon interaction cross section. Here we present a summary of that work, describe recent technical improvements, and results from new calibrations. Prospects for the future of the LUX scientific program are reported, together with the outlook for its successor project, LZ.

Cold darkmatter particles with an intrinsic matter-antimatter asymmetry do not annihilate after gravitational capture by the Sun and can affect its interior structure. The rate of capture is exponentially enhanced when such particles have self-interactions of the right order to explain structure...... formation on galactic scales. A `dark baryon' of mass 5 GeV is a natural candidate and has the required relic abundance if its asymmetry is similar to that of ordinary baryons. We show that such particles can solve the `solar composition problem'. The predicted small decrease in the low energy neutrino...

As evinced by multiple astrophysical measurements, a large fraction of the matter in the Universe is in the form of a dark, non-baryonic component. If darkmatter interacts weakly with the Standard Model it could be produced at the LHC, escaping the ATLAS detector and thus leaving a signature of large missing transverse momentum. If this interaction is mediated by a kinematically accessible mediator, then that mediator can also give rise to a dijet resonance signature. The latest results of these dijet resonance searches are presented, and their limitations and future prospects discussed.

The DAMA/LIBRA set-up (about 250 kg highly radiopure NaI(Tl) sensitive mass) is running at the Gran Sasso National Laboratory of the I.N.F.N.. The first DAMA/LIBRA results confirm the evidence for the presence of a DarkMatter particle component in the galactic halo, as pointed out by the former DAMA/NaI set-up; cumulatively the data support such evidence at 8.2 σ C.L. and satisfy all the many peculiarities of the DarkMatter annual modulation signature. The main aspects and prospects of this model independent experimental approach will be outlined.

The results from searching for darkmatter either directly from invisible decay of Higgs bosons or in association with a Higgs boson at the LHC are presented. No significant excess is found beyond the Standard Model prediction, and upper limits are set on the production cross section times branching fraction using data collected in proton-proton collisions at center-of-mass energies of 13 TeV by the ATLAS and CMS detectors. An interpreted upper limit is presented on the allowed darkmatter-nucleon scattering cross section.

We study tachyonic preheating associated with the spontaneous breaking of B-L, the difference of baryon and lepton number. Reheating occurs through the decays of heavy Majorana neutrinos which are produced during preheating and in decays of the Higgs particles of B-L breaking. Baryogenesis is an interplay of nonthermal and thermal leptogenesis, accompanied by thermally produced gravitino darkmatter. The proposed mechanism simultaneously explains the generation of matter and darkmatter, thereby relating the absolute neutrino mass scale to the gravitino mass. (orig.)

We study tachyonic preheating associated with the spontaneous breaking of B-L, the difference of baryon and lepton number. Reheating occurs through the decays of heavy Majorana neutrinos which are produced during preheating and in decays of the Higgs particles of B-L breaking. Baryogenesis is an interplay of nonthermal and thermal leptogenesis, accompanied by thermally produced gravitino darkmatter. The proposed mechanism simultaneously explains the generation of matter and darkmatter, thereby relating the absolute neutrino mass scale to the gravitino mass. (orig.)

AH dynamical evidence points to the conclusion that the predominant form of matter in the universe is in a non-luminous form. Furthermore, large scale deviations from uniform Hubble flow, and the recent COBE reports of inhomogeneities in the cosmic microwave background strongly suggest that we live in an exactly closed universe. If this is true, then ordinary baryonic matter could only be a minority component (10% at most) of the missing mass, and that what constitutes the majority of the darkmatter must involve new physics. The axion is one of very few well motivated candidates which may comprise the darkmatter. Additionally it is a `cold` dark-matter candidate which is preferred by the COBE data. We propose to construct and operate an experiment to search for axions which may constitute the darkmatter of our own galaxy. As proposed by Sikivie, dark-matter axions may be detected by their stimulated conversion into monochromatic microwave photons in a tunable high-Q cavity inside a strong magnetic field. Our ability to mount an experiment quickly and take data within one year is due to a confluence of three factors. The first is the availability of a compact high field superconducting magnet and a local industrial partner, Wang NMR, who can make a very thermally efficient and economical cryostat for it. The second is an ongoing joint venture with the Institute for Nuclear Research of the Russian Academy of Sciences to do R&D on metalized precision-formed ceramic microwave cavities for the axion search, and INR has commited to providing all the microwave cavity arrays for this experiment, should this proposal be approved. The third is a commitment of very substantial startup capital monies from MIT for all of the state-of-the-art ultra-low noise microwave electronics, to one of our outstanding young collaborators who is joining their faculty.

We used the neutral atomic hydrogen data of the Very Large Array for the spiral galaxy NGC 5921 with z = 0.0045 at the distance of 22.4 Mpc, to investigate the nature of darkmatter. The investigation was based on two theories, namely, darkmatter and Modified Newtonian Dynamics (MOND). We presented the kinematic analysis of the rotation curve with two models of darkmatter, namely, the Burkert and NFW profiles. The results revealed that the NFW halo model can reproduce the observed rotation curve, with χ 2_{red}≈ 1, while the Burkert model is unable to fit the observation data. Therefore, the darkmatter density profile of NGC 5921 can be presented as a cuspy halo. We also tried to investigate the observed rotation curve of NGC 5921 with MOND, along with the possible assumption on baryonic matter and distance. We note that MOND is still incapable of mimicking the rotation curve with the observed data of the galaxy.

On August 17, 2017 the LIGO interferometers detected the gravitational wave (GW) signal (GW170817) from the coalescence of binary neutron stars. This signal was also simultaneously seen throughout the electromagnetic (EM) spectrum from radio waves to gamma rays. We point out that this simultaneous detection of GW and EM signals rules out a class of modified gravity theories, termed "darkmatter emulators," which dispense with the need for darkmatter by making ordinary matter couple to a different metric from that of GW. We discuss other kinds of modified gravity theories which dispense with the need for darkmatter and are still viable. This simultaneous observation also provides the first observational test of Einstein's weak equivalence principle (WEP) between gravitons and photons. We estimate the Shapiro time delay due to the gravitational potential of the total darkmatter distribution along the line of sight (complementary to the calculation by Abbott et al. [Astrophys. J. Lett. 848, L13 (2017)], 10.3847/2041-8213/aa920c) to be about 400 days. Using this estimate for the Shapiro delay and from the time difference of 1.7 seconds between the GW signal and gamma rays, we can constrain violations of the WEP using the parametrized post-Newtonian parameter γ , and it is given by |γGW-γEM|<9.8 ×10-8.

Indirect detection of darkmatter is a major avenue for discovery. However, baryonic backgrounds are diverse enough to mimic many possible signatures of darkmatter. In this work, we study the newly proposed technique of darkmatter velocity spectroscopy [E. G. Speckhard, K. C. Y. Ng, J. F. Beacom, and R. Laha, Phys. Rev. Lett. 116, 031301 (2016), 10.1103/PhysRevLett.116.031301]. The nonrotating darkmatter halo and the Solar motion produce a distinct longitudinal dependence of the signal which is opposite in direction to that produced by baryons. Using collisionless darkmatter only simulations of Milky Way like halos, we show that this new signature is robust and holds great promise. We develop mock observations by a high energy resolution x-ray spectrometer on a sounding rocket, the Micro-X experiment, to our test case, the 3.5 keV line. We show that by using six different pointings, Micro-X can exclude a constant line energy over various longitudes at ≥3 σ . The halo triaxiality is an important effect, and it will typically reduce the significance of this signal. We emphasize that this new smoking gun in motion signature of darkmatter is general and is applicable to any darkmatter candidate which produces a sharp photon feature in annihilation or decay.

Supersymmetric radiative neutrino mass models have often two darkmatter candidates. One is the usual lightest neutralino with odd R parity and the other is a new neutral particle whose stability is guaranteed by a discrete symmetry that forbids tree-level neutrino Yukawa couplings. If their relic abundance is comparable, darkmatter phenomenology can be largely different from the minimal supersymmetric standard model (MSSM). We study this in a supersymmetric radiative neutrino mass model with the conserved R parity and a Z 2 symmetry weakly broken by the anomaly effect. The second darkmatter with odd parity of this new Z 2 is metastable and decays to the neutralino darkmatter. Charged particles and photons associated to this decay can cause the deviation from the expected background of the cosmic rays. Direct search of the neutralino darkmatter is also expected to show different features from the MSSM since the relic abundance is not composed of the neutralino darkmatter only. We discuss the nature of darkmatter in this model by analyzing these signals quantitatively

The cosmological concordance model contains two separate constituents which interact only gravitationally with themselves and everything else, the darkmatter and the dark energy. In the standard dark energy models, the darkmatter makes up some 20% of the total energy budget today, while the dark energy is responsible for about 75%. Here we show that these numbers are only robust for specific dark energy models and that in general we cannot measure the abundance of the dark constituents sepa...

The search for constituents that can explain the periods of accelerating expansion of the Universe is a fundamental topic in cosmology. In this context, we investigate how fermionic fields minimally and non-minimally coupled with the gravitational field may be responsible for accelerated regimes during the evolution of the Universe. The forms of the potential and coupling of the model are determined through the technique of the Noether symmetry for two cases. The first case comprises a Universe filled only with the fermion field. Cosmological solutions are straightforwardly obtained for this case and an exponential inflation mediated by the fermion field is possible with a non-minimal coupling. The second case takes account of the contributions of radiation and baryonic matter in the presence of the fermion field. In this case the fermion field plays the role of dark energy and darkmatter, and when a non-minimal coupling is allowed, it mediates a power-law inflation. (paper)

The current cold darkmatter cosmological model explains the large scale cosmic web structure but is challenged by the observation of a relatively smooth distribution of matter in galactic clusters. We consider various aspects of modeling the darkmatter around galaxies as distributed in smooth halos and, especially, the smoothness of the darkmatter halos seen in N-body cosmological simulations. We conclude that the problems of the cold darkmatter cosmology on small scales are more serious than normally admitted.

The current cold darkmatter cosmological model explains the large scale cosmic web structure but is challenged by the observation of a relatively smooth distribution of matter in galactic clusters. We consider various aspects of modeling the darkmatter around galaxies as distributed in smooth halos and, especially, the smoothness of the darkmatter halos seen in N-body cosmological simulations. We conclude that the problems of the cold darkmatter cosmology on small scales are more serious than normally admitted

The standard model of particle physics is marvelously successful. However, it is obviously not a complete or final theory. I shall argue here that the structure of the standard model gives some quite concrete, compelling hints regarding what lies beyond. Taking these hints seriously, one is led to predict the existence of new types of very weakly interacting matter, stable on cosmological time scales and produced with cosmologically interesting densities--that is, ''darkmatter''. copyright 1995 American Institute of Physics

Halo darkmatter, if it is baryonic, may plausibly consist of compact stellar remnants. Jeans mass clouds containing 10 to the 6th to 10 to the 8th solar masses could have efficiently formed stars in the early universe and could plausibly have generated, for a suitably top-heavy stellar initial mass function, a high abundance of neutron stars as well as a small admixture of long-lived low mass stars. Within the resulting clusters of dark remnants, which eventually are tidally disrupted when halos eventually form, captures of neutron stars by nondegenerate stars resulted in formation of close binaries. These evolve to produce, by the present epoch, an observable X-ray signal associated with darkmatter aggregations in galaxy cluster cores.

results from indirect and direct detection darkmatter search experiments is given. .... Such particles can be very light but still be CDM since their interaction was so extremely weak that they could not thermalize in the early Universe. ..... was caused by the report of two events in the signal region, the first time direct detection.

Recent studies of low redshift type Ia supernovae (SN Ia) indicate that half explode from less than Chandrasekhar mass white dwarfs, implying ignition must proceed from something besides the canonical criticality of Chandrasekhar mass SN Ia progenitors. We show that 1-100 PeV mass asymmetric darkmatter, with imminently detectable nucleon scattering interactions, can accumulate to the point of self-gravitation in a white dwarf and collapse, shedding gravitational potential energy by scattering off nuclei, thereby heating the white dwarf and igniting the flame front that precedes SN Ia. We combine data on SN Ia masses with data on the ages of SN Ia-adjacent stars. This combination reveals a 2.8σ inverse correlation between SN Ia masses and ignition ages, which could result from increased capture of darkmatter in 1.4 vs 1.1 solar mass white dwarfs. Future studies of SN Ia in galactic centers will provide additional tests of dark-matter-induced type Ia ignition. Remarkably, both bosonic and fermionic SN Ia-igniting darkmatter also resolve the missing pulsar problem by forming black holes in ≳10 Myr old pulsars at the center of the Milky Way.

In this review, we recall how stars contribute to the search for darkmatter and the specific role of the Sun. We describe a more complete picture of the solar interior that emerges from neutrino detections, gravity and acoustic mode measurements of the Solar and Heliospheric Observatory (SOHO) satellite, becoming a reference for the most common stars in the Universe. The Sun is a unique star in that we can observe directly the effect of darkmatter. The absence of a signature related to Weakly Interacting Massive Particles (WIMPs) in its core disfavors a WIMP mass range below 12GeV. We give arguments to continue this search on the Sun and other promising cases. We also examine another darkmatter candidate, the sterile neutrino, and infer the limitations of the classical structural equations. Open questions on the young Sun, when planets formed, and on its present internal dynamics are finally discussed. Future directions are proposed for the next decade: a better description of the solar core, a generalization to stars coming from seismic missions and a better understanding of the dynamics of our galaxy which are all crucial keys for understanding darkmatter.

We show that a couplet, a pair of closely spaced photon lines, in the X-ray spectrum is a distinctive feature of lepton flavored darkmatter models for which the mass spectrum is dictated by Minimal Flavor Violation. In such a scenario, mass splittings between different darkmatter flavors are determined by Standard Model Yukawa couplings and can naturally be small, allowing all three flavors to be long-lived and contribute to the observed abundance. Then, in the presence of a tiny source of flavor violation, heavier darkmatter flavors can decay via a dipole transition on cosmological timescales, giving rise to three photon lines. Two of these lines are closely spaced, and constitute the couplet. Provided the flavor violation is sufficiently small, the ratios of the line energies are determined in terms of the charged lepton masses, and constitute a prediction of this framework. For darkmatter masses of order the weak scale, the couplet lies in the keV-MeV region, with a much weaker line in the eV-keV region. This scenario constitutes a potential explanation for the recent claim of the observation of a 3.5 keV line. The next generation of X-ray telescopes may have the necessary resolution to resolve the double line structure of such a couplet.

DarkMatter, Neutrinos, and Our Solar System is a unique enterprise that should be viewed as an important contribution to our understanding of darkmatter, neutrinos and the solar system. It describes these issues in terms of links, between cosmology, particle and nuclear physics, as well as between cosmology, atmospheric and terrestrial physics. It studies the constituents of darkmatter (classified as hot warm and cold) first in terms of their individual structures (baryonic and non-baryonic, massive and non-massive, interacting and non-interacting) and second, in terms of facilities available to detect these structures (large and small). Neutrinos (an important component of darkmatter) are treated as a separate entity. A detailed study of these elusive (sub-atomic) particles is done, from the year 1913 when they were found as byproducts of beta decay -- until the discovery in 2007 which confirmed that neutrino flavors were not more than three (as speculated by some). The last chapter of the book details t...

We develop a hybrid formalism suitable for modeling scalar field darkmatter, in which the phase-space distribution associated to the real scalar field is modeled by statistical equal-time two-point functions and gravity is treated by two stochastic gravitational fields in the longitudinal gauge (in

A technique for reducing the microphonic noise in a germanium spectrometer used in darkmatter particles searches is described. Filtered energy spectra, corresponding to 48.5 kg day of data in a running experiment in the Canfranc tunnel are presented. Improvements of this filtering procedure with respect to the method of rejecting those events not distributed evenly in time are also discussed. (orig.)

The gravitino is a promising supersymmetric darkmatter candidate which does not require exact R-parity conservation. In fact, even with some small R-parity breaking, gravitinos are sufficiently long-lived to constitute the darkmatter of the Universe, while yielding a cosmological scenario consistent with primordial nucleosynthesis and the high reheating temperature required for thermal leptogenesis. In this paper, we compute the neutrino flux from direct gravitino decay and gauge boson fragmentation in a simple scenario with bilinear R-parity breaking. Our choice of parameters is motivated by a proposed interpretation of anomalies in the extragalactic gamma-ray spectrum and the positron fraction in terms of gravitino darkmatter decay. We find that the generated neutrino flux is compatible with present measurements. We also discuss the possibility of detecting these neutrinos in present and future experiments and conclude that it is a challenging task. However, if detected, this distinctive signal might bring significant support to the scenario of gravitinos as decaying darkmatter. (orig.)

ture of the darkmatter (DM) in the Universe, from the point of view of particle ... they must be electrically and (preferably) color neutral. .... in the general MssM and in two unification-based models: the constrained MssM ..... multi-TeV range.